X-linked recessive inheritance

In this video, we learnt about X-linked recessive inheritance.

X-linked recessive conditions are caused by a gene alteration on the X chromosome. As males have only one X chromosome, if they have a gene alteration on their X chromosome they will develop the condition.

Females rarely show signs of X-linked recessive conditions as they usually have a second unaltered copy of the gene on their other X chromosome to compensate for an altered gene.

A female who has a gene alteration on one of her X chromosomes is said to be a carrier for the X-linked recessive condition.

Features of X-linked recessive inheritance include:

• Males are affected almost exclusively.
• The gene mutation can be transmitted from female carriers to sons.
• Affected males cannot transmit the condition to their sons.

An example family pedigree depicting X-linked recessive inheritance Click to expand
_{© St George’s, University of London}

In the next step you will be introduced to an X-linked recessive condition, Duchenne Muscular Dystrophy, caused by a mutation/deletion affecting the dystrophin gene.

_{Image ©“Nick van Steendelaar” by Partij van de Arbeid. Licensed by CC BY 2.0}