Rhizomelic Chondrodysplasia Punctata: Type 1

Rhizomelic chondrodysplasia punctata type 1 (RCDP1) is an inherited peroxisomal disorder characterized by shortening of the upper arms and thighs. Children with RCDP1 will also develop stiff and painful joint deformities, severe intellectual disability, seizures, and breathing problems. If not already present at birth, they will also develop cataracts in the first few months of life. Children with RCDP1 usually do not survive past the age of 10. A milder form of the disorder has been recognized, where individuals have lived into early adulthood, but it is also much less commonly seen. RCDP1 is caused by pathogenic variants in the PEX7 gene.

RCDP1 is inherited in an autosomal recessive manner. This type of inheritance requires the presence of two copies of a pathogenic variant in the gene for a person to have the genetic disease. Both parents must be carriers of a pathogenic variant in the gene in order to be at risk to have an affected child. The child must inherit a pathogenic variant from each carrier parent in order to be affected. There is a 1 in 4 chance that a baby will inherit two mutated copies of the gene and be affected when both parents are carriers.

There are generally no signs or symptoms associated with being a carrier for RCDP1. However, the risk to have a child affected with RCDP1 is increased. Testing of reproductive partners is recommended for carriers of RCDP1.

RCDP1 is a rare disorder, affecting less than 1 in 100,000 newborns. RCDP1 is not known to be specific to any particular ethnic group.

Genetic Home Reference: Rhizomelic Chondrodysplasia Punctata (http://ghr.nlm.nih.gov/)
Genetic Alliance: Rhizomelic Chondrodysplasia Punctata type 1 (http://www.diseaseinfosearch.org/)

OMIM [RCDP1: 215100] (http://www.ncbi.nlm.nih.gov/omim)
Gene Reviews: Rhizomelic Chondrodysplasia Punctata type 1 (http://www.ncbi.nlm.nih.gov/books/NBK1116/)

• Full gene sequencing