And so some of the more familiar sex-linked traits are hemophilia, red-green color blindness, congenital night blindness, some high blood pressure genes, Duchenne muscular dystrophy, and also Fragile X syndrome. In each pregnancy, if the mother is a carrier and the father has the disease, the expected outcomes are:.
Editorial team. X-linked dominant disorders are caused by mutations in genes on the X chromosomeone of the two sex chromosomes in each cell.
Carla Easter, Ph. Example: baldness in humans. X and Y are sex chromosomes. X-linked dominant disorders are caused by mutations in genes on the X chromosomeone of the two sex chromosomes in each cell.
There is no male to male transmission.
For this mode of inheritance, males get their gene for the trait from their mother. In males who have only one X chromosomeone altered copy of the gene in each cell is sufficient to cause the condition. These conditions are usually inherited in one of several patterns, depending on the gene involved:.
However, this is not technically correct.
One form of a gene may be dominant over another form which is recessive and the dominant form would be expressed. The X chromosome will contain the alleles for the trait and the Y chromosome will have no alleles for this trait.
These are characters only expressed in one sex. Goldman-Cecil Medicine. Lippincott Company. Textbook of Family Medicine.