Tuesday, July 24, 2012

Genetics 103: Questions & Answers (Hopefully)

I'm well aware of the fact that my cell looks more like an over-easy egg, but I hope this helps to clarify  the following (and last set of) questions:

1. Are neuromuscular problems genetic in origin?

Not all neuromuscular disorders are genetic, but there are many that are. Some examples of genetic neuromuscular disorders include spinal muscular atrophy and the different types of Charcot-Marie-Tooth disorder. These conditions can be a challenge to diagnose, but it is important to determine when a neuromuscular patient may have a genetic cause, as then it can impact other family members.

Answer by: Angela Filose: I work as a full-time genetic counselor for a Kaiser hospital, working with prenatal, pediatric, and hereditary cancer patients.

2. What is mitocondrial DNA, where did it come from and why is it needed? 

In humans, mitochondrial DNA spans about 16,500 DNA base pairs, representing a small fraction of the total DNA in cells. Mitochondrial DNA contains 37 genes, all of which are essential for normal mitochondrial function. It is inherited solely from your mother. Many genetic conditions are related to changes in particular mitochondrial genes.

Answer by: Anna Rossoshek, M.S., M.B.A.: I work in the Chemical Genomics Branch at NCTT/DPI. My work encompasses a broad scope of functions that allows me to utilize my education, both scientific and business management, in addition to the experience I have gained through many years as a Biologist in an NIH Intramural Lab and as a Scientific Administrative Analyst in the Division of Extramural Research at NHGRI. I currently assume the role of a Project Manager for the four main scientific sections of the branch. Those sections include Tox21, RNAi Screening, Chemistry Technology Development, and Assay Development and Screening Technology.

3. Can a genetic test such as whole exome sequencing detect mitocondrial disorders?

Good question! Mitochondrial diseases can be caused by mutations in either the mitochondrial genome (a small circular chromosome found within the mitochondria) or by mutations in the nuclear genome (on the chromosomes found in the nucleus). Whole exome sequencing is typically done in such a way that only the exons in the nuclear genome are captured and sequenced, and thus, will only identify some of the mutations associated with mitochondrial disease. Some labs will also do a separate analysis of the mitochondrial genome to identify those mutations.

Answer by:  Hooker, Ph.D., Sc.M.:I am the Associate Director of the Johns Hopkins Bloomberg School of Public Health/National Human Genome Research Institute Genetic Counseling Training Program and a contracted staff scientist within the Social and Behavioral Research Branch of the NHGRI. Prior to entering the field of genetic counseling, I completed my Ph.D. in Molecular, Cellular and Developmental Biology.

4. Do you see the whole exome sequencing test being available to the general public and covered by insurance companies any time soon?

Great question. I don't see this happening in the very near future, but I do see the possibility for public access to whole exome sequencing becoming a reality in the next 20-30 years. It may still be too expensive for many at that point, but also available to many. 

Your question about whether insurance companies would actually pay for this testing is complicated. I think we would have to prove that whole exome testing would be useful to our medical providers. That is something I think will take much longer than 20 years. Genetics is complicated by the fact that our technilogical advances, our ability to see information, is improving much faster than our ability to understand that information. 

That takes much more work since we are talking about how our genetics affect our body's functioning, and our bodies are very complex. We also have to take into account how our bodies are affected by the environment we live in. Lastly, we need to understand the social and ethical implications of being able to get this information. Is it something, as a society, that we want the general public to have access to? There are many of these discussions going on and many more that need to happen as we develop these technological abilities. 

Answer by: Ami Rosen: For the past 10 years I've provided genetic counseling to people at risk for developing Huntington's Disease. I am also a neurogenetics research coordinator, well-versed in the ethical concerns of human subjects research and DNA banking. 

5. Do you see things such as "genetic discrimination" happening in the near future?

They are definitely possible, so that's why it's important that we take measure now to prevent them through legislation, promoting awareness, and developing guidelines for the professionals involved. Right now, individuals are protected by GINA (Genetic Information Non-discrimination Act), where health insurance companies cannot discriminate someone based on his/her genetic testing results. In the future, we may also move towards establishing legislative protection from genetic discrimination from other sources, like disability insurance, life insurance, etc. 

Answer by: Julia Su: I am a second year genetic counseling student from Sarah Lawrence College (graduate May 2012). I have rotated through several genetics clinics in the New York area and Toronto. I am highly passionate about genetics, as well as the integration of psychosocial counseling in clinical genetics services.

6. Is the structure of the DNA molecule something that was originated randomly? or was it designed? 

The structure of DNA (the double-helix) is the way it is out of necessity. This structure, which resembles a twisted ladder, makes it possible for each DNA strand to be precisely copied. These copies, which contain the same genetic information as the original DNA strand, can then be passed along to an organism's offspring. I'm not sure when DNA first evolved into its double-helix structure. Sounds like a chicken-and-egg problem!

Answer by: Becky Clark: I am a genetic counselor and research associate in an ophthalmic genetics department. I counsel patients on inherited retinal disorders and manage a repository and database for genetic testing research. 

I wasn't too happy with the last response, but in all fairness, that is a whole other debate worthy of it's own chat session. I really believe that I answered my own question better in this post: Fearfully and Wonderfully made.

With that said, I'm very grateful for the opportunity to chat with the experts in the subject because it did help me get some more understanding over the things that happened to us, it had a great therapeutic value for me, I hope that it has the same value for you, if you stumbled upon this post.

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