Pyknoachondrogenesis

Definition

A rare lethal chondrodysplasia characterized by severe generalized osteosclerosis. Main clinical manifestations include large head, palpebral edema, flat nose, low-set ears, hexagon-like mouth, a short neck (hidden by skin folds), a short and wide trunk, a prominent abdomen, and severe micromelic dwarfism with rather normal-length hands and feet. X-rays show marked sclerosis of the facial bones and extremities, and poor ossification elsewhere. It has a lethal outcome, either prenatally or during the early neonatal period. There have been no further descriptions in the literature since 1986.