Re: passing on CMT question

[Guest guest]

,

In X linked CMT, the CMT gene is carried on the female sex

chromosome. The disease is inherited by males from their mothers, who

are carriers. The mother will typically have no symptoms at all or be

mildly affected.

Each of her sons will have a 50 percent chance of having CMT, and an

affected son is likely to be more severely affected than his mother.

Each of the girls has a 50 percent chance of being a carrier.

A male affected with X-linked CMT cannot pass the disorder to his

sons, but all of his daughters will be carriers of the disorder.

r females have a 50 percent chance of passing the disorder to

their sons. Unaffected children cannot pass the disorder onto their

children since they don't carry the gene.

Gretchen

[Guest guest]

Hey Gretchen:

So, you mean a man can actually have CMT-X & there is absolutely NO chance of

passing it on to the sons?

Oh! Please bear with me as I think & type...That must be because the male is

XY, female XX...father passes on only the Y chromosome to his son, while the son

gets his X chromosome from mother. In the case of a daughter, however, she

would get one X chrom. from both father AND mother, therefore a 100% chance the

daughter will have the CMT gene.

Am I on the right track? Just trying to understand & bring up my college

genetics from the back of my brain, ouch!

Thanks & Blessings,

Holly

[Guest guest]

Hi Holly,

Right about X linked CMT. In Type 1X, the CMT gene is on the female

sex chromosone. CMT is inherited by males (from their mothers) and

the mothers are 'carriers'. Sometimes those mothers might not have

any CMT symptoms, or her symptoms may be so mild they are not noticed.

Each of a mother's sons will have a 50% chance of having CMT

and may be affected greater than his mother. The mother's daughters

have a 50 & chance of being a carrier.

A male affected with X-linked CMT cannot pass the disorder to his

sons, but all of his daughters will be carriers of the disorder.

There are five type of X now, some are recessively inherited, so I

think there's more to this genetically. Especially with the axonal

forms http://neuromuscular.wustl.edu/time/hmsn.html

Consider the source here - lol, but I flunked Biology, and instead of Genetics,

I opted for Art History (something I could understand, lol!)

Gretchen