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How is biotechnology used to make predictions about fetal health conditions? Modern techniques can analyze DNA without invasive sampling, and a lot may be learned about fetal health from a mother's blood test. Board certified genetic counselor Daniel Weisman of the University of Florida describes the amazing new molecular techniques that can diagnose potential fetal/neonate risks in the fetus or parents. Such tests allow for better family planning and addressing neonate needs at birth and in the subsequent time.
Talking Biotech is a weekly podcast that uncovers the stories, ideas and research of people at the frontier of biology and engineering.
Each episode explores how science and technology will transform agriculture, protect the environment, and feed 10 billion people by 2050.
Interviews are led by Dr. Kevin Folta, a professor of molecular biology and genomics.
Biotech Fetal Diagnostics - Daniel Weisman, Board Certified Genetic Counselor, University of Florida
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[00:00:00] Kevin Folta: Hi
everybody, and welcome to this week's Talking Biotech podcast by Collabora. Now one of the places where modern molecular biology tools have made a tremendous impact is in the area of prenatal screening. Now, there was a time not long ago when we knew very little about what was happening at the level of a developing fetus.
You could listen to heartbeats and you had ultrasounds that came along and other diagnostic tools that you could use, but nothing that could predict some of the major problems that could happen. Things like Down Syndrome, for instance. Later on, amniocentesis would come in and in other ways that you could start to assess genetic genetic integrity of the fetus.
And we've talked about that a little bit here on the podcast. But recently I've learned of new ways that, of diagnostics, new things that could happen. And I wanted to talk to an expert. We're speaking with Daniel Weisman. He's a manager of genetic counseling, a board certified genetic counselor at the University of Florida.
So welcome to the podcast.
[00:01:04] Daniel Weisman: Hello. Thank you for having
[00:01:04] Kevin Folta: me. Yeah, this is super cool. Why is prenatal genetic counseling so important? It
[00:01:10] Daniel Weisman: could be hard to explain the value, the importance of genetic counseling. For the most part, not many people actually know what genetic counseling is. So even before you get to the value, you know, the importance of it.
A lot of people, they just literally have no idea what I do. So essentially, The biggest importance of genetic counseling would be communication. So hopefully your genetic counselor is an effective communicator where they can translate these complex ideas, concepts, they can interpret your complex test result in ways that a patient would be.
Able to understand so into more digestible parts. And then from a, I, I guess again, from a patient's perspective, a genetic counselor really should be a patient advocate. So one of the main. directives of genetic counseling is non directiveness. So I, I think I said that in a weird way, but, you know essentially I'm not paternalistic.
It's not my job to tell you what you should do, how you should plan your family, but coming up with how you want to plan your family. So using your personal goals, beliefs, morals, and sort of helping decide how much information you want, how far you're willing to go to get that information. So then, In terms of just patient care, I'm, I'm a patient advocate.
So then explaining test results, going through all of your different options, really creating a personalized plan. . And then from the clinic background I'm really a big tool for the physicians to use just again, in, in terms of communicating with patients. So then doctors who use lots of medical jargon, it can be really difficult to understand exactly the point that the doctor's getting across.
The physician has limited time in the exam room where then I just have more time to spend with the. more opportunity to talk about things with them and really again, sort of personalize things for them and their family. So, you know, in terms of prenatal genetic counseling in the office, I see myself having two different roles.
One would be fetal risk assessment. What's the chances that your baby has, if it's down syndrome or a birth defect? And risk can come from lots of different places. And then number two, prenatal diagnosis. So I'm not a physician, I don't touch people, I don't do procedures. But how good is your blood test?
How good is the ultrasound? Do you need the amniocentesis? Those are the main two topics that I would sort of emphasize to a.
[00:03:38] Kevin Folta: Yeah, one part I didn't really appreciate is the counseling aspect, so it's not just enough to be able to interpret reports and understand the science. You have to be really adept at connecting with people at a human level to help guide them to appropriate decisions.
[00:03:55] Daniel Weisman: and it can be a very stressful decision. So then you know, we can go through numbers and statistics all day, but a lot of family planning choices are just based on personal factors. So then what number child this is for you? You know, hey, to bring up money, but how much money do you guys make? How strong your relationship is, how strong your marriage is, what your religion is.
There's all these personal factors that people use to decide. You, you know, we would. To be medical based, but in the real world it's not black or white people. You know, there's shades of gray and it can be sort of hard to distinguish, to choose the right path and it's coming up with whatever is right for them and their family.
That's the right path for the patient to take.
[00:04:37] Kevin Folta: So our all expected parent parents going through genetic counseling or is it really just certain types of parents that have maybe a little more advanced?
[00:04:48] Daniel Weisman: Genetic counseling does not necessarily have to be provided by a board certified genetic counselor.
So physicians can definitely provide genetic counseling nurses, nurse practitioners, midwives. So then you, you know, I see very few pregnant women that come through the department, so you have to jump through a bunch of hoops that necessarily get to me. , but genetic counseling itself, again, is, is not limited to me.
So providers are definitely performing their own genetic counseling. You know, in, in terms of risk, well, you can identify risk of various different ways. Most of the time it might be just based on a woman's age, but given her personal history, her family history, her ethnicity there's lots of different ways that you can define risk.
[00:05:32] Kevin Folta: and what are some of the routine tests that are performed just on a average everyday person who's coming through, who's pregnant and what, what are we doing now that may be a little different than we did even just a decade or two ago?
[00:05:45] Daniel Weisman: Well, down Syndrome has been around for a long time. Down syndrome.
Testing's been around for a long time, but there's a newer technology. That's much more accurate in determining your risk for having a child with Down Syndrome. So in terms of routine testing, everybody, all pregnant women should be offered aneu ploy screening for the reason that these are not necessarily hereditary conditions.
They almost always happen by chance. So again, everybody has risk. It's whether or not you're aware of it or not. So in terms of routine testing, all pregnant women should be offered down syndrome, aneu ploy screening. There's also what you call carrier screening, which is testing the patient herself for autosomal recessive traits.
But you can test for sex link traits. So, you know, in terms of routine testing, It really depends on the doctor's office and how, what their protocol is. But generally speaking, down Syndrome, what you call Trisomy 18. Trisomy 13. And then you can look at other things like cystic fibrosis spinal SCL atrophy, fragile X hemoglobinopathy, stuff like that.
[00:06:54] Kevin Folta: Yeah. And some of those are dictated by the ethnicity of the parent or family history, that kind of thing. More than more than just testing across everybody. Right? There's, there's some like red flags that go off that maybe suggest these are important tests. Yep. So then
[00:07:08] Daniel Weisman: historically, in terms of carrier screening, it was based on how you identify, you know, if you think that you have a Jewish background or not, or if you're African American.
If you're Asian, Hispanic, everybody carries a handful of traits. Typically, it doesn't make a difference cuz your partner's not gonna carry the same trait. But certain individuals may have a higher chance to carry a trait, but it generally only matters if you both carry the same trait. .
[00:07:35] Kevin Folta: Yeah. So are these tests all PCR based where they just get a little bit of maternal blood and then make a little d n a and test away?
Or is that how this works?
[00:07:44] Daniel Weisman: It depends on the nature of the condition. So then, you know, PCR r Yes. In the sense that it involves genetic testing, you know, is it always sequencing or common mutation analysis? Well there would be, you know, trinucleotide repeat disorders like fragile X syndrome. Sometimes it's not even necessarily genetic testing.
Rather, you could do a hemoglobin electrophoresis test for sickle cell beta thalassemia. So then there's a, a few different ways that you can go about getting some genetic information
[00:08:15] Kevin Folta: and when they talk about carrier screening, when they look at the mother and they maybe screen her blood for a, you know, whatever number of, of recessive autosomal traits are there, or how many do they test for, and what are some common ones they might look for?
[00:08:32] Daniel Weisman: American College, obstetric, gynecology, acog, American College of Medical Genetics, A C M G. They both have some standard guidelines to offer. Women cystic fibrosis screening, spinal muscular atrophy screening, hemoglobinopathy screening. So that's kind of the, the bare minimum that people should be offered.
Depending on family history, if there's a family history of autism or intellectual disability, you could do fragile X syndrome nowadays, given the, the, the cost has gone. From any of these tests, they would perhaps offer a pan-ethnic panel where it may not necessarily be tailored to your identified ethnicity, but it covers a variety of different conditions from different ethnicities.
The same concept as what you call expanded carrier screen, where you could test for 1, 2, 3, but you could test for 10, 100, 200, even maybe more than 300 different. .
[00:09:32] Kevin Folta: Yeah. If there's one thing we learned from services like 23 and Me is that most of us don't really know what our ethnicities really are.
[00:09:40] Daniel Weisman: Yeah. What The family story may not be accurate. Mm-hmm. ,
[00:09:44] Kevin Folta: right? Yeah. I mean, and that, and that maybe they're, maybe they're may be traits that, that may be worth screening for. And so they don't really test the father unless the mother comes back positive, or how do they, what's, how do they draw that?
[00:09:56] Daniel Weisman: Yeah, because they're autosomal recessive.
So then if mom is negative or normal, you stop there. If she's positive, then you'd offer her partner the same test because it's the combination of the parents. Versus, you know, there are gonna be sex link conditions, fragile X Duchenne muscular dystrophy where you're only testing the mother, where then she has a risk to have a son affected.
But a lot of this stuff is recessive where it's the combination of the parents.
[00:10:20] Kevin Folta: Yeah. And I guess these. More sensitive tests than used to be done. So what, what were the ways that this was done previously?
[00:10:27] Daniel Weisman: Well, I mean, just to use cystic fibrosis as an example, it's all pcr, it's all sequencing, but historically they're only testing for common mutations.
So then if you're a carrier for cystic fibrosis, . Typically it happens at some hotspots, a, B, C, or D, you know, with the lower cost of genetic count genetic testing, sorry. You know, next gen sequencing, things like that. They can offer full gene sequencing where they're looking at the entire gene A through Z, which is gonna have a much higher mutation detection rate.
So the, if you truly are a carrier, sequencing is gonna have a much better ability to detect it versus maybe something like a common mutation analysis. . So then there's kind of, again, guidelines out there for laboratories to test, you know, how many mutations or y y you know sort of ways to test things.
So then you can kind of do some old school testing, but you can go big, you can really test for a whole lot.
[00:11:22] Kevin Folta: Yeah. Well, what was old school testing?
[00:11:25] Daniel Weisman: Well, you know, in terms of prenatal testing so far we have focused mostly on molecular testing given the nature of your podcast. But I mean, there's things out there.
So maternal serum alpha fetal protein, to have a child with spina bifida, there is the quad screen. A little bit more recently, things like first trimester screening where, you know, these are aneuploidy tests. They're looking for down syndrome, but they may be hormone. Based on patterns of hormones, it determines your risk.
The thing about that technology, why it's been replaced by the cell-free DNA is it's just not looking at the cause. So then down syndrome is Trisomy 21, not necessarily a hormone condition. You had a lot of false positives in the past. So it's not uncommon where a woman has a story like, Hey, they told me my baby.
Has Down syndrome and the child's born perfectly normal. So nowadays that old school testing is being replaced by newer generation of sequencing technology where the, again, the lab can be much more precise in determining risk for the baby to have a condition or their ability to detect if you're truly a carrier or
[00:12:32] Kevin Folta: not.
No. Very cool. So we're speaking with Daniel Weisman. He's a manager of genetic counseling at the University of Florida. He's a board certified genetic counselor who's talking to us about the modern molecular tools that can be diagnostic in prenatal counseling or prenatal advising of parents with respect to potential medical conditions that are happening before a child is born.
And we'll be back with collabs talking biotech podcast in just a moment. And now we're back on collabs talking Biotech podcast. We're speaking with Dan Weisman. He's a manager of genetic counseling at the University of Florida, a board certified genetic counselor who is helping parents understand.
The genetics of the unborn child who's coming along. And I ran in the Dan through kind of a, a circuitous method in that I'm expecting a daughter in May. And when we got news on this back in August We were really lost because we didn't know what to do next. And, and both of us are advanced age parents and I sent a quick note over to someone here at the university and they got me in touch with, with Dan, and he was extremely helpful in helping me understand what was going to happen over the next couple of weeks.
And it's. Gone as planned. Dan. Everything looks really cool and it's been really fun. It was fun to go into this having a conversation with you first because everything the physicians came to me with was stuff I heard about already. Yeah. So thank you for that. That's awesome. Congratulations. Yeah, thank you.
It really was helpful. Some of the things that were really important that you mentioned right off the bat when we talked the first time was. , there's advances in high throughput sequencing, which really have changed what this early diagnostic screenings are. And are things like amniocentesis even performed anymore or is everything really just take a little bit of maternal blood and do high throughput sequencing and either look for discreet genetic changes or maybe misrepresentation.
Specific chromosome parts, like how, what's happening now?
[00:14:38] Daniel Weisman: Yep. So then just for perspective, maternal blood for things like Down Syndrome is never gonna be diagnostic. It's never gonna say a hundred percent yes or no. It has very high detection rates. For example, cell-free D n A should detect approximately 99% of cases of Down syndrome.
So then if your child truly has it, 99% of the time it's gonna flag it as a high risk. But as your. a hundred percent, no, but it would still be very high. Might range anywhere from 50 to 90%, but that's going to be orders of magnitude greater than what it should be, generally speaking, based on an age related risk.
So the number of amniocentesis that, so amnios, dawn, routinely every day. The number of procedures has gone down dramatically. But I would say if you do an amniocentesis, you actually have a higher chance for an abnormal. Because we're doing it for better reasons nowadays. So then now we can give people good news.
A lot of patients, a lot of people think I focus only on the negative, bad. A lot of my job is actually giving good news where hey, The doctor calls you old, but just for perspective, your age risk is less than 1% to have a child with Down syndrome. Your blood testing came back negative or normal based on the blood work.
Well, you have approximately one in 10,000 chance to have a child with downs. You know, again, it's not zero, but that's literally as good as it gets. So then quad screen, stuff like that. You had to do an am. because it wasn't very specific and the newer technologies didn't exist. So we definitely do choreo Phyllis sampling c bs in the first trimester.
We do amniocentesis in the second trimester, but certainly the number of procedures has gone down. Just cuz again, we can give good news where maybe in the past they couldn't give the same level of. ,
[00:16:31] Kevin Folta: you know, and there's also risk associated with the procedure itself, right? I mean, I, I know someone I know who had an amniocentesis that preceded a stillbirth.
[00:16:41] Daniel Weisman: Yep. So then in terms of risk, historically, ACOG would recom they quote a one in 200 chance for miscarriage due to cvs, a one in 300 chance for miscarriage due to amniocentesis. Newer studies have shown a a much lower chance. I think it was the faster trial showed one in 1600 risk for miscarriage.
Due to amniocentesis. We quote sort of a middle. Nowadays we're quoting about a one in 500 chance for miscarriage due to cvs, a one in 800 risk for miscarriage due to amniocentesis. The studies that look at the risk, you know, they can go out the entire length of the pregnancy, but over time there's so many other things that could happen.
If you, if you, if you're gonna have a complication because of one of those procedures, typically it's gonna happen that day. That. You would note it sooner rather than later. But they are invasive. CVS is a placental biopsy. It's performed one of two different ways. Amnio is the classic needle on the belly test.
They take the fluid out. So they are invasive, they are uncomfortable. They do come with risk. When we offer these procedures, generally when we offer it, what we're really communicating is that the risk that we're gonna. A diagnosis on, on one of these procedures is greater than the risk for mis. .
[00:17:55] Kevin Folta: I see.
So that makes a lot of sense. Well, I love this self free stuff, and you've mentioned this a couple times, so let's clarify exactly what this is. So when a woman is pregnant and she's af passed a certain time, like I guess it's 10 weeks into the pregnancy, that. There is a certain amount of fetal blood that is present that's circulating in her system that can be used as a diagnostic tool.
I mean, do I have that right or is it fetal cells that are being shed or where or is placental or what? What's going on
[00:18:26] Daniel Weisman: there? Yeah, so close cell-free d n A are small fragments. They may be 100, 200 base pair long. So what happens is cells from your body die. They break open, they release fragments of dna.
Cells from the placenta die, break open in release fragments of the dna. So then the laboratory captures these fragments and based on the sequence, they can determine the chromosome of origin. So they'll say this comes from chromosome number one. This comes from chromosome 21. So they do what they, this process called binning, where basically they put the stuff in a bucket.
They take the number of fragments from chromosome 21 and they compare it to a reference. Certain stuff just has to be normal. Like you can't have a trisomy one in a pregnancy for the most part, because you wouldn't be pregnant. It's just not compatible with life. If the lab finds the proper amount of dna N.
everything is in the correct representation. The mother and the pregnancy are both normal, but if they ever find extra d n a, so there's extra 21 compared to the reference. They're saying Mom is normal. She does not have Down syndrome. It has to come from somewhere else. That can only be the pregnancy, so then that would mean there's a high likelihood that your child has that chromosome problem.
But like you just said, it's a placenta. It's not a baby test. The placenta and the baby come from the same embryo. Genetically speaking, they should be identical. And that's almost always the case, but very rarely they're not. So then if you wanna further confuse people, we can get into mosaicism, , but essentially, you know, placenta's.
We know they can acquire abnormalities. I don't think that we knew how common it was for placenta to acquire abnormalities, but anytime you do a CVS procedure, there's about a one to 2% chance that you can find a mixture of cells. Certain percentage are normal, but the remaining percentage are not. The thing about that is the blood test is sensitive enough to detect that.
So then with the cell-free dna, it's not cells, it's not fetal blood, it's fragments of the dna N and it's a placenta test, not a baby test. The other reason that cell-free DNA is not diagnostic, it doesn't give you the. So it's all based on computers and equations, but not physically looking at the dna, and that's where the CVS and the amniocentesis come into play, where then you get the carry type using the microscope.
You can count the number, look at the structure of the chromosomes. If there's an extra chromosome, you can literally point at it. So that's why it tells you for certain, versus blood work is very good, but just not diagnostic.
[00:21:15] Kevin Folta: Yeah. This is basically just telling you if something is misrepresented Yeah. It, it, there's too much of this one where it shouldn't be and that could be that could be suggestive of some other kind of problem we should look at further.
Is that kind of where that goes? Exactly.
[00:21:29] Daniel Weisman: And because it's looking at the chromosomes, it's much more accurate telling you that inform. .
[00:21:38] Kevin Folta: Yeah. And so is this kind of thing, so nowadays this is done pretty early though. In a pregnancy, it's like at 10 weeks,
right?
[00:21:44] Daniel Weisman: That's generally the window when it starts. So most all labs except blood at 10 weeks, there are a lab, like one or two labs that might go week earlier at nine weeks.
One of the issues with the early gestational age, you know, it, it sounds attractive. Hey, we can get this done, but you might be limited in the sense that you need to get into your OB office, you gotta have your. Initial prenatal visit, so then sometimes you don't get it done exactly at 10 weeks just because of the logistics of the office.
[00:22:13] Kevin Folta: Yeah, that's true. But at the same time, you know, and, and maybe this is an area you don't want to get into, but with all the laws around termination of pregnancy, things like that, where. Which don't have any allowance for fetal condition or, or maternal health that you may at early is good to be able to make decisions early in a pregnancy rather than having something that's detected at week, you know, 16 or 20.
[00:22:40] Daniel Weisman: Exactly. So, you know, without getting controversial OB offices, generally speaking, should be aware of what you're talking about and at least moving in the direction. Everything's going early, everything blood works early, ultrasounds early it's all going that direction.
[00:22:57] Kevin Folta: And what about markers for things like neural tube defects?
[00:23:01] Daniel Weisman: Well, okay. Not everything's genetic. So then, you know, spina bifida hole in the spine, neural tube defects. Ultrasound is the primary, the, the primary tool for diagnosis of neural tube defects. In the second trimester you have alpha fetal protein, but that blood test. Detection rates are maybe 70 to 80%, and you have a lot of false positives.
So then in the hand of a practiced sonographer and experienced physician ultrasound will tell you yes or no about spina bifida. The AFPs on the way out, just like the quad screen. It's just an old school technology. You know, ultrasounds, advanced technology's gotten a higher resolution where they can see these details.
Just physically looking at the. .
[00:23:44] Kevin Folta: And what about things like telling the baby's sex without doing an ultrasound? How reliable are the screens for detection of a y chromosome, that kind of thing? Yeah,
[00:23:54] Daniel Weisman: so in fact, that's probably what most people wanna know is the gender of the baby. I can guarantee you there's women who do this blood testing, they don't necessarily recognize its down syndrome testing.
Rather they know it's gender testing. So when they do the cell-free, they can look for the presence of the Y chromosome. If it's not there, you got a baby girl. If it's there, you can ha you, you have a baby boy. So then cell-free dna, I would say is probably about 99% accurate for determining the gender.
But we always confirm that using ultrasound So then it's all the same test. The gender is just on the Down syndrome report. You know, if you're really trying to find gender, well, there's actually direct to consumer gender testing where I think you can do it as early as six or seven weeks. They're doing cell-free DNA at the lab, but they're only using it for gender purposes.
But I would say that if you know you're gonna do down syndrome testing, you're probably gonna pay for that test. And you might not necessarily need to pay for an extra test because the Down Syndrome test will tell you the gender. You just gotta wait a little bit.
[00:25:02] Kevin Folta: Yeah, it's just kind of a funny story because we knew that the baby was coming and we were sharing this with our family, but we, and we did this test, this cell-free test and we.
Said we would do a gender reveal, but we weren't gonna do something dumb like shoot fireworks or something. We said, what we'll do is we'll get everybody together and we will read the report at the same time everybody's together on a Zoom call. You know? Cause we all live in different places in the country and we had everybody on and my wife starts going through the report and it doesn't say male or female or a pink or blue or whatever.
It doesn't give you a a. You know, indication as to what they found. And so she spent about 15 minutes, everyone's bored, everyone's getting ready to hang up, . And finally I looked at it and it says, no Y chromosome detected. And that's, that's actually what they tell you. So all I know is that there's no y chromosome detected.
I'm, I'm guessing that it is likely. To be female. So that's it was just kind of interesting how that came together for us. But
[00:26:03] Daniel Weisman: yeah, they definitely make you read through the lines. You know, one thing that this technology can tell you that many patients may not be aware is sex chromosome antiquity.
So then you can have extra or missing Xs and Ys, and that's something that's not really on a lot of people's radar that that blood test could also tell you. You may or may not want to know,
[00:26:24] Kevin Folta: you know, how, how common is Y chromosome manup. ,
[00:26:28] Daniel Weisman: X, Y, Y is what you call Jacob syndrome. So then my understanding maybe like just as common as Down syndrome, if not more common, the thing about X, Y, Y, there's also other conditions.
X X Y Klein filters, there's Triple X. A lot of people who have those problems have no idea that they have that condition because they may not necessarily. Problems that you have to go to the doctor for, where you can have some delays, you can have some learning problems, but maybe they're not significant, significant enough that you're getting referred to a geneticist for a microarray or a karyotype.
So then those things are actually very common, but also unrecognized in many people. .
[00:27:10] Kevin Folta: Yeah. I remember years ago it was very controversial that looking at X, Y, y suggesting that maybe they were more aggressive or more people in prison with X, Y, Y and that they really just kind of don't test for that routinely unless it.
Seems to partner with other types of physical abnormalities or, you know, or beha or physiological abnormalities. Is that still pretty much the case? No,
[00:27:33] Daniel Weisman: not at all. So that's what I was taught to. Classic old school textbook would teach you that. The thing is, if you test abnormal populations, yes, you can find that type of thing, but once you start testing normal people, you find it a lot more.
So then they don't think x, y, Y creates criminals anymore. Essentially, if you have a learning disability, maybe you would make a bad choice, or perhaps you put yourself in not a great situation with other people. You know, you just maybe a little bit more vulnerable. And I think that's the explanation right now.
But a lot of that stuff is just variation of normal. So then you know, X, y, y, yes, you might be a little bit tall, but if your family's tall to begin, , then you're probably just gonna be part of the pack. You know, if you're kind of shorter to begin with and you're an inch taller, well then your normal height learning disabilities can sometimes go along with that.
But generally speaking, you don't expect intellectual disability. There's not a consistent pattern of birth defects. So I wanna say like 90% of men with X, y, y have no idea that they have it, or about 70% of men with kleinfeld. have no idea that they have it because they're just normal people.
[00:28:46] Kevin Folta: Huh. I would never would've guessed that from the old school textbooks.
[00:28:49] Daniel Weisman: Yeah, no counseling has dramatically changed, so then it's really a variation of normal. You have a lot of positives on cell-free dna n a for those conditions. This might be the one instance that cell-free. Technology is, it's just not as good as it is compared to other conditions like Down syndrome, meaning that you have a lot more false positives.
The labs would argue that they're probably not false positives. The placenta or mosaic, maybe placenta's could tolerate those issues a little bit more. It's not very scientific, but a little bit better compared to other chromosome abnormalities. So then, What you call positive predictive values are a lot lower for sex chromosome antiquity compared to, let's say, down syndrome.
Yeah,
[00:29:37] Kevin Folta: no, that's a really interesting point because if you think about the old school textbooks, this is back at a time where if somebody presents with some sort of specific spectrum of, of mm-hmm. physiological or anatomical de deficiencies, that they would then do the Caro type and say, ah, obviously here's.
You know, Kleinfeld or whatever, and the, the folks who were normal, who didn't show symptoms weren't being diagnosed that way. And so that totally skewed the earlier literature on these particular disorders. That's it really did. Yeah. So, you
[00:30:10] Daniel Weisman: know, it was just, it was just really biased. But. Yeah. So you know, we, it's not uncommon to go through those types of results, but generally speaking, we try to be as reassuring as possible and we just have a lot more false positives for those types of conditions.
So then Information can be good, but information can be bad. , and there's such thing as too much information and y you know, that might be one example where hey, like, you know, it's not gonna necessarily cause intellectual disability. It's not necessarily gonna cause birth defects. Prenatal detection probably has a better outcome versus postnatal detection for the reason that postnatally, you're doing it, you're finding out for a reason.
The kid has developmental delays, they're dysmorphic, maybe they have a birth defect versus prenatally. It's almost always incidental just by.
[00:30:53] Kevin Folta: Oh, what's next for genetic counselors? I mean, what's the holy grail of prenatal testing that's not currently available? Like what would you really like to know that could help parents make better decisions?
[00:31:05] Daniel Weisman: That's a tough question. So, holy Grail, my first thought would be non-invasive diagnostic testing. I would think that that may not be cell-free though, so y you know, just a maternal blood test to say definitively. yes or no about genetic diseases is, is, is still it's still, well, it's a pipe dream.
So then, you know, where we're at right now is cell-free DNA is expanding. So then we've talked about autosomal anlody. So trisomy 13, 18, 21. We've talked about sex chromosome, Anup ploy, extra missing Xs and Ys. Cell-free DNA can look for micro deletions. So DeGeorge Syndrome 22 Qre Shot WeHo. A few others.
Whole genome cell-free. DNA N is already available, but test performance is kind of unknown, so they can't necessarily tell you how good they are looking at other chromosomes besides 13, 18 21. Whole exome sequencing. Whole genome sequencing are already clinically available, but you have to do an invasive procedure.
So then in terms of genetic testing, every day there's new tests added to the menu. The, the, the menu's only growing, so then the role for the genetic counselor is only expanding. The 21st century is going in the direction of genetics. So not everything is genetic, but. Just more and more testing you do, the more you learn and the more it just creates more and more business.
Yeah,
[00:32:30] Kevin Folta: and I think that's really bodes well for job security. I tell all my students this all the time. I say stay in biotech and stay in genetics. Because this is another interesting part as we get into the area of personalized genetics, you know, I've had guests on the podcast who said that before you go to the physician, you're going to have a blood test that's going and you're going to have a complete genome sequence that you'll go in and give a report to your physician about here's what's going on genetically with.
Yep. And, and will, those kinds of reports, how valuable will those kinds of reports be to take mom and dad and before they even consider losing birth control? mm-hmm. , I mean, are there certain people that maybe just shouldn't be reproducing and we can make those calls before they even get, you know, knee deep in the process?
[00:33:18] Daniel Weisman: So. Yes and no. So will that, will technology get there? I think so. Again, not everything's genetic, so then there's always environmental factors. There's environmental triggers. So then in certain conditions, whether it be diabetes, high blood pressure, high cholesterol, mental illness, there's genetic factors, but it's tough to prove causation where, you know, you might have more of a susceptibility, a predisposition, but again, there's gonna be environmental things out there that would.
Overflow the glass if you're born with your glass half full. Yeah. So y you know, is that kind of where it's going? Probably. But at the same time there's just limitations to knowledge. So even with whole XM sequencing, I mean, what does that look at? Like 1% of the genome, whole genome sequencing is burdensome in the sense that it's just way too much information.
It's just difficult to manage. You can find, can. Candidate genes. I mean, you're gonna find variants of uncertain significance, so you're just gonna find a lot of stuff at the moment that we may not understand.
[00:34:22] Kevin Folta: Yeah, no, that, that makes perfect sense. I, I guess I just kind of start to extrapolate a little bit based upon, you know, my interest in the field.
But when we talked about this idea about the, you know, the future of job security and op opportunities in these areas. What does that future look like for genetic counseling? And what kind of degrees would you recommend and the types of training you know different degree levels, what's going to be necessary for students who right now really are intrigued with the idea of genetic counseling?
Genetic
[00:34:53] Daniel Weisman: counselors can come from a variety of different backgrounds. You don't necessarily have to be a biology major or a chemistry, or even a genetics major. There's gonna be certain core curriculum that you have to take, but you could be psychology, you could be social, where, I mean, you can come from nursing.
There's lots of different backgrounds, so, genetic counseling is almost a hundred percent employment. It's just a matter where you wanna work and what you want to do. So then genetic counseling is consistently ranked in like the 100 top jobs for the US news in America, or, you know, whatever that magazine is.
So then there's always jobs. It kind of depends on where you want to go, what you want to do. Genetic counseling is a very small niche profession, so I wanna say just this year, There was 5,000 board certified genetic counselors in the United States. So then there's a lot more programs popping up.
There's a lot training programs are getting bigger. Typically class sizes are very small. They're trying to expand it. One of the issues with getting trained for genetic counseling is finding trainer trainers. So then it's just tough to find genetics clinics. Genetics is really underserved, but genetic counseling.
Was recently there was licensure in the state of Florida, and that's a nationwide trend where we're now just being recognized as pro like clinical providers. So then, yeah, it, it, it is, it, it's great job security, you know, it's, it's only gonna get bigger. They're only gonna do more. So in that sense it's very exciting.
Even I've been doing this for over 10 years now. Things have really dramatically changed since I've been, since I started.
[00:36:22] Kevin Folta: Yeah, I, I think it's gonna be even more interesting. I'm, I'm really glad we talked about this, because I think I would rather have a genetic counselor who is a little bit more of a psychologist than, and who knows how to deal with people, a communicator than a scientist who has a bunch of numbers and.
Front of them and, and, and, and I think that I really see the magic in this. Luckily we haven't had to interact with any genetic counselors because everything's coming out rosy. But it's one of these things that I, I think going forward as I'm advising students, this seems like a really good place to think about cuz it just seems like our opportunities will be,
[00:37:01] Daniel Weisman: Yeah, and I, I think a lot of physicians recognize that as well, where we might have a better ability to communicate.
I mean, literally you take training in genetic counseling programs for, you know, risk risk discussion, how you give results. So then, I mean, these are things that we literally practice that we train for. So then it just, some news was probably delivered in a more empathetic manner. The language itself is easier to understand.
Mm-hmm. Versus maybe, you know, the doctor is very, yeah. very, very, very smart, but maybe not the best
[00:37:37] Kevin Folta: communicator. Yeah. The empathy of a molecular biologist is is you typically leaves something to be desired. . Yeah. Yeah. So thank you very much for your time today. If people wanted to learn more your program or prenatal, genetic counseling in general, or what's happening at the University of Florida?
Where would they look? Either online or maybe social?
[00:37:55] Daniel Weisman: Online would be a great place. So not even just restricting it to University of Florida, but the National Society of Genetic Counselors, nsgc.org is a great place to go. You can find genetic counselors in your area if you do need to talk to someone, but there's a lot of stuff on training for students.
There's a lot of information for prote prospective patients of you know, what exactly that you're walking into. Cause again, even from the beginning, Many patients don't necessarily know what genetic counseling is. They don't, it's, it's a big unknown. They think it's like psychosocial counseling, sit on the couch and talk to a therapist.
There's a little bit of emotional aspect, but it's more hard science again, result, conversation, that type of stuff. Interpreting family trees, pedigrees. So those squares and circles that you learn during biology class, we still do that. Yeah, so then I would, I would say National Society of Genetic Counselors, nsgc.org would be a great re
[00:38:43] Kevin Folta: All right, so Dan Weisman, thank you very much for your time today.
This is really great stuff. And you know, if anything ever comes up new breakthroughs, new opportunities, new ways in which this is being done, can you please get back to us and let's do this again. Yeah, absolutely. Thanks for the opportunity. And as always, thank you for listening to another episode of The Talking Biotech podcast.
Share this episode with someone who's expecting asking questions about what's happening in the womb in terms of diagnostics that can help. Parents either make decisions before or be ready for challenges after a child is born can be really important, and it's a really important technology that's based on that D n A stuff.
So thank you very much for listening, and we'll talk to you again next week.