Rhizomelic chondrodysplasia punctata type 1 (RCDP1) is a disorder that affects the size of the body, bones, intellectual abilities, and eyes.
In the classic form, children usually have shorter arm and leg bones and are born smaller than usual. They don’t grow as expected, making them much smaller than other kids. The cartilage in their joints has round or oval areas of hardening, causing stiffness and pain. Their facial features are distinctive. Unfortunately, most children with the classic form don’t live past 10 years old, and some don’t even make it through infancy. They often face severe mental disability, with limited skills similar to a six-month-old. Seizures are common, along with rough and scaly skin, a cleft palate, and spine malformations. Early cataracts cloud their vision, and recurrent lung infections can be life-threatening.
In the milder form, intellectual and growth issues are less severe. Some may have shortened limbs, and all experience cartilage hardening and cataracts. While there’s no cure for RCDP1, surgery can remove cataracts and improve vision. Physical therapy may help maintain movement, and other bone surgeries might be beneficial. Many children with the disease need a feeding tube, and close monitoring of lung function is crucial to prevent infections. Those with milder forms may benefit from a specialized diet.
RCDP1 is caused by pathogenic (disease-causing) variants in the PEX7 gene and exhibits autosomal recessive inheritance. This means that both parents must be carriers to have a 25% chance to have a child with the condition. The risk of being a carrier is based on a person’s ancestry or ethnic background. For example, individuals of Ashkenazi Jewish descent have a 1 in 234 chance to be a carrier.