Rhizomelic chondrodysplasia punctata (RCDP) is a genetic disorder which is clinically characterized by rhizomelic shortening of the upper extremities, dysmorphic facial features, congenital contractures and severe growth and mental retardation. Alpha-oxidation of phytanic acid and plasmalogen synthesis that takes place in the peroxisomes are impaired in patients with RCDP. However, a significant biochemical heterogeneity within RCDP has been established recently. Clinical heterogeneity has also been observed among many patients.
Based on the associated mutations, five types of RCDP (RCDP1-5) have been identified. RCDP2 (Rhizomelic chondrodysplasia punctata type 2) is associated with mutations in GNPAT gene. Consequently, patients with RCDP2 have acyl-CoA:dihydroxyacetonephosphate acyltransferase (DHAPAT) deficiency, which in turn disrupts plasmalogen synthesis.