your are hear » Home » About CMT » What is CMT » Basic Genetics
X-linked or sex-linked recessive - CMT Type 1X
Article Index
Page 3 of 5
These conditions are determined by genes which are carried on one of the chromosomes which control the sex of a child. The result is that only boys are affected and they inherit the disease from their mothers who are known as carriers. Carriers are capable of passing the condition on to their own sons. Women who carry the gene can either be completely unaffected, in which case they tend to be known as "carriers"; or they may be mildly affected, or they may have the condition as severely as males. This is because all female mammals have a problem with gene dosage. Each adult woman when she was an embryo randomly suppressed one or other of her X chromosomes in each cell in her body. If she carried the variant gene on the X chromosome, then it may be that this X chromosome is active in most cells in the relevant tissue, e.g. nerve cells, leading to neuropathy. Each son of a carrier has a 50% chance of having CMT 1X and each daughter has a 50% chance of being a carrier.
Unaffected boys cannot transmit the disease: however, the daughters of a man with X-linked CMT are all carriers.
