What are the genetic changes related to rhizomelic chondrodysplasia punctata ?
Rhizomelic chondrodysplasia punctata results from mutations in one of three genes. Mutations in the PEX7 gene, which are most common, cause RCDP1. Changes in the GNPAT gene lead to RCDP2, while AGPS gene mutations result in RCDP3.  The genes associated with rhizomelic chondrodysplasia punctata are involved in the formation and function of structures called peroxisomes. Peroxisomes are sac-like compartments within cells that contain enzymes needed to break down many different substances, including fatty acids and certain toxic compounds. They are also important for the production of fats (lipids) used in digestion and in the nervous system.  Within peroxisomes, the proteins produced from the PEX7, GNPAT, and AGPS genes play roles in the formation (synthesis) of lipid molecules called plasmalogens. Plasmalogens are found in cell membranes throughout the body, although little is known about their function. Mutations in the PEX7, GNPAT, or AGPS genes prevent peroxisomes from making plasmalogens. Researchers are working to determine how problems with plasmalogen synthesis lead to the specific signs and symptoms of rhizomelic chondrodysplasia punctata.