Bartsocas-Papas syndrome is a rare, inherited, popliteal pterygium syndrome (see this term) characterized by severe popliteal webbing, microcephaly, a typical face with short palpebral fissures, ankyloblepharon, hypoplastic nose, filiform bands between the jaws and facial clefts, oligosyndactyly, genital abnormalities, and additional ectodermal anomalies (i.e. absent hair, eyebrows, lashes, nails). It is often fatal in the neonatal period, but patients living until childhood have been reported.

Pterygia are 'winglike' triangular membranes occurring in the neck, eyes, knees, elbows, ankles or digits.