Popliteal pterygium syndrome

Popliteal pterygium syndrome (PPS) is a rare inherited genetic disorder characterized by distinctive craniofacial, musculoskeletal and genitorourinary symptoms. It is primarily caused by a mutation to the IRF6 gene and follows an autosomal dominant inheritance pattern. The syndrome is associated with many features such as popliteal webbing (pterygium), cleft lip or palate, syndactyly, and genetic anomalies with the severity and expression of each symptom varying between affected individuals. PPS has an approximate incidence rate of 1 in every 300 000 live births. The condition was first described by Trélat in 1869 and later named by Gorlin and colleagues in 1968. The term pterygium is derived from the Greek word for "wing," referring to the wing-like tissue structures often observed in affected individuals.