Rhizomelic chondrodysplasia punctata (RCDP) is a rare genetic condition that affects the normal development of many parts of the body. It is characterized by the shortening (rhizomelia) of two proximal bones, the humerus (the long bone of the upper arm) and the femur (the thigh bone). Another distinguishing feature is the abnormal calcification of cartilage at the ends of the long bones (chrondrodysplasia punctata).
Rhizomelic chondrodysplasia punctata type 1 (RCDP1) is caused by genetic variation in the PEX7 gene. The Pex7 protein is responsible for transporting several enzymes into the peroxisome, a membrane-bound compartment found in cells that hold enzymes required to break down fatty acids. Affected people do not produce enough Pex7 protein, leading to abnormal fatty acid breakdown. Symptoms of RCDP1 result from the inability to produce a specialized fat molecule known as plasmalogen, found on cell membranes.
Take this test to find out whether you are a genetic carrier of the PEX7 variant and are at risk of passing it to your children. This is intended to be a carrier screening test for couples who are considering to start a family.
Rhizomelic chondrodysplasia punctata type 1 is caused by genetic variation in the PEX7 gene, which gives instructions produce a protein necessary to assemble functional peroxisomes. People with the variant produce a defective Pex7 protein, which affects the production of a special fat molecule known as plasmalogen, leading to symptoms associated with the condition.
RCDP1 is inherited in an autosomal recessive pattern, which means two defective copies of the PEX7 gene must be inherited in order for the disease to manifest.
This test looks at one genetic variant of the PEX7 gene linked to rhizomelic chondrodysplasia punctata type 1 in carriers of European descent.
- rs1805137 A variant (L292X)
Understanding your carrier status will help you understand the risk of passing on rhizomelic chondrodysplasia punctata to your children.
While a carrier do not typically show signs and symptoms of the condition there is a 25% chance the child will inherit the disease if both parents are carriers.
Characteristic symptoms include
- Shortening of the humerus and femur (known as rhizomelia)
- Abnormal build up of cartilage at the end of bones
- Joint issues
- Cataracts at birth or develop early in life
- Severe intellectula disabilities
- Frequent lung infections
- Failure to grow and develop
- Distinct facial features – prominent forehead, widely set eyes, small nose with upturned nostrils, sunken appearance in the middle of the face, and full cheeks
How It Works
Step 1: Sign up for a free Genebase account.
Step 2: Upload your DNA markers to Genebase.
Step 3: Login to your account to access your results when they are ready.