Metatropic dysplasia is a skeletal disorder characterized by short stature (dwarfism) with other skeletal abnormalities. The term "metatropic" is derived from the Greek word "metatropos," which means "changing patterns." This name reflects the fact that the skeletal abnormalities associated with the condition change over time.

Metatropic dysplasia is caused by mutations in the TRPV4 gene, which provides instructions for making a protein that acts as a calcium channel. The TRPV4 channel transports positively charged calcium atoms (calcium ions) across cell membranes and into cells. The channel is found in many types of cells, but little is known about its function. Studies suggest that it plays a role in the normal development of cartilage and bone. This role would help explain why TRPV4 gene mutations cause the skeletal abnormalities characteristic of metatropic dysplasia. Mutations in the TRPV4 gene appear to overactivate the channel, increasing the flow of calcium ions into cells. However, it remains unclear how changes in the activity of the calcium channel lead to the specific features of the condition.

Metatropic dysplasia is a rare disease; its exact prevalence is unknown. More than 80 affected individuals have been reported in the scientific literature.

Metatropic dysplasia is considered an autosomal dominant disorder because one mutated copy of the TRPV4 gene in each cell is sufficient to cause the condition. Most cases of metatropic dysplasia are caused by new mutations in the gene and occur in people with no history of the disorder in their family. In a few reported cases, an affected person has inherited the condition from an affected parent.

Published Date: April 01, 2012Published By: National Institutes of Health