CMT Genetics

[Guest guest]

I asked some questions of the CMT genetics expert from the University of

Washington because there were some statements in this newsletter that

contradicted other statements, and I thought people basing decisions on genetic

information should be clear. Following are my questions and his answers.

Elinor

1) Does each succeeding CMT generation have worse symptoms with any or all the

types?

No, this phenomenon (also called genetic anticipation) is not seen in any known

form of CMT.

2) Is the chance of inheritance in any type of CMT greater than 50% if only one

parent has the gene?

No, the maximum risk for a form of CMT is 50% (i.e. autosomal dominant CMT).

3) Does non-X-linked CMT tend to be passed on from father to daughter and mother

to son?

Dominant CMT affects males and females equally, and the risk to an affected

person for passing it on to a son or daughter is 50% at each mating.

4) Should asymptomatic children and/or healthy adults be tested?

Generally, asymptomatic, at-risk minors are not tested as it does not help with

their medical care.

[Guest guest]

Thank you for the clarifications, Elinor.

This is the same information my genetics counselor at Wayne State

(affiliated with Dr. Shy) shared with me. Anecdotal reports and science

don't always seem to match because we become biased by what we see in our

day-to-day lives, which is only a small segment of the rest of the world.