Pyknodysostosis: report of a rare case with review of literature

Pyknodysostosis, which was first described in 1962 by Maroteaux and Lamy, is a rare autosomal recessive disorder of osteoclast dysfunction causing osteosclerosis. The name derives from the Greek "pyknos" meaning "dens". These authors speculated that the famous French painter, Toulouse-Lautrec (1864-1901), may have suffered from this disease. The disease shows equal sex distribution with high parental consanguinity, having an incidence of 1.7 per 1 million births. 2,3 A common finding in this disorder is a greater tendency for fractures, especially of the long bones. Spontaneous fractures of the mandible during mastication are uncommon and are usually due to trauma, exodontias, and post-osteomyelitis. eneral features of pyknodysostosis include short stature under 150 cm, generalized diffuse osteosclerosis with a tendency for fracture after minimal trauma, hypoplastic clavicles, as well as acro-osteolysis with sclerosis of the terminal phalanges which is an essential pathognomonic feature. Other features include wrinkled skin, finger and nail abnormalities, kyphosis and scoliosis, history of repeated chest infections, and sleep apnea. The intellectual and sexual development is usually normal in the patients. ranial and maxillofacial features include frontoparietal bossing, thick calvaria, open fontanelles and sutures, hypoplastic paranasal sinuses, wormian bones in the lambdoidal region, relative proptosis, beaked nose, hypoplastic midface, and obtuse mandibular gonial angle, often with relative prognathism. 5