Slide show: How genetic disorders are inherited
Illustration of X-linked recessive inheritance with carrier mother
Previous Next 6 of 6 X-linked recessive inheritance pattern with carrier mother

In an X-linked inheritance pattern, the mutated gene is on the X chromosome. Duchenne muscular dystrophy, some types of colorblindness and hemophilia A are examples of X-linked recessive disorders.

For a person to have a recessive disorder, it usually requires two copies of the mutated gene. However, males are affected by a single X-linked recessive gene from their mother because they don't have a second X chromosome to override the recessive trait.

A woman who is a carrier of an X-linked recessive disorder has a 25 percent chance of each of the following results with each pregnancy:

  • Having an unaffected son
  • Having an unaffected daughter
  • Having an unaffected daughter who also is a carrier
  • Having an affected son

Genetic counseling

If you know — or suspect — that you or your partner has a family history of any genetic disorder, a genetic counselor can help assess your risk of having a child with that disorder. This counselor can also help you decide whether to have genetic testing and explain treatments, preventive measures and reproductive options.

See more Multimedia May 21, 2014