X-linked cardiac valvular dysplasia is a condition characterized by the abnormal development (dysplasia) of heart (cardiac) valves. The normal heart has four valves, two on the left side of the heart and two on the right side, that allow blood to move through the heart and prevent blood from flowing backward. In X-linked cardiac valvular dysplasia, one or more of the four heart valves is thickened and cannot open and close completely when the heart beats and pumps blood. These malformed valves can cause abnormal blood flow and an irregular heart sound during a heartbeat (heart murmur).

X-linked cardiac valvular dysplasia is caused by mutations in the FLNA gene. This gene provides instructions for producing the protein filamin A, which helps build cells' extensive internal network of protein filaments called the cytoskeleton. The cytoskeleton gives structure to cells and allows them the flexibility to change shape. Filamin A primarily attaches (binds) to another protein called actin and helps it form the branching network of filaments that make up the cytoskeleton.

The prevalence of X-linked cardiac valvular dysplasia is unknown. Approximately 3 percent of the population has a heart valve defect, only a small fraction of which are associated with X-linked cardiac valvular dysplasia.

This condition is inherited in an X-linked pattern. A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes in each cell. In males, who have only one X chromosome, a mutation in the only copy of the gene in each cell is sufficient to cause the condition. In females, who have two copies of the X chromosome, one altered copy of the gene in each cell can lead to less severe features of the condition or may cause no signs or symptoms at all. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.

Published Date: March 01, 2018
Published By: National Institutes of Health