Why is Rett syndrome found only in human females?
A) It is a recessive mutation located on the X chromosome and two copies are required to show the disease.
B) It is a dominant mutation on the X chromosome and you need both copies of the mutation to show the disease.
C) It is caused by a loss-of-function mutation of MeCP2 that is only expressed in females because it is silenced in males.
D) It is caused by a loss-of-function mutation of MeCP2, and X-linked gene, and when this is silenced in males, they often die prenatally or as infants.

Question

Quizplus · Accepted Answer

Rett syndrome is an X-linked gene and loss-of-function MECP2 mutations in females result in genetic mosaics depending on which cells have the defective MeCP2 inactivated. Males only have one copy on the X-chromosome so when that copy is inactivated it leads to severe developmental defects and early death.

Why Is Rett Syndrome Found Only in Human Females