Pyknodysostosis: visceral manifestations and simian crease.

Pyknodysostosis is a rare autosomal recessive osteosclerosing skeletal disorder caused by mutations in the CTSK gene situated at 1q21 that codes for cathepsin K - a lysosomal cysteine protease. Mutations in this gene affect the metabolism of skeletal system. This causes problems in bone resorption and remodelling and craniofacial abnormalities. In this article we report a case of 12 year old female from Punjab with pyknodysostosis having hepatosplenomegaly and simian crease.