X-linked chondrodysplasia punctata 2 is a disorder characterized by bone, skin, and eye abnormalities. It occurs almost exclusively in females.

X-linked chondrodysplasia punctata 2 is caused by mutations in the EBP gene. This gene provides instructions for making an enzyme called 3β-hydroxysteroid-Δ8,Δ7-isomerase, which is responsible for one of the final steps in the production of cholesterol. Cholesterol is a waxy, fat-like substance that is produced in the body and obtained from foods that come from animals (particularly egg yolks, meat, poultry, fish, and dairy products). Although too much cholesterol is a risk factor for heart disease, this molecule is necessary for normal embryonic development and has important functions both before and after birth. It is a structural component of cell membranes and plays a role in the production of certain hormones and digestive acids.

X-linked chondrodysplasia punctata 2 has been estimated to affect fewer than 1 in 400,000 newborns. However, the disorder may actually be more common than this estimate because it is likely underdiagnosed, particularly in females with mild signs and symptoms.

This condition is inherited in an X-linked dominant pattern. The gene associated with this condition is located on the X chromosome, which is one of the two sex chromosomes. In females (who have two X chromosomes), a mutation in one of the two copies of the EBP gene in each cell is sufficient to cause the disorder. Some cells produce a normal amount of 3β-hydroxysteroid-Δ8,Δ7-isomerase and other cells produce none. The resulting overall reduction in the amount of this enzyme underlies the signs and symptoms of X-linked chondrodysplasia punctata 2.

Published Date: November 01, 2011
Published By: National Institutes of Health