Pycnodysostosis with unusual findings: a case report

Quais Mujawar,Ravi Naganoor,Sadashiva Ukkali,Naushad Malagi,Harsha Patil,Achyut Narayan Thobbi

doi:10.4076/1757-1626-2-6544

Abstract

Pycnodysostosis is a rare clinical entity, first described in 1962 by Maroteaux and Lamy. The disease has also been named Toulouse-Lautrec syndrome, after the French artist Henri de Toulouse-Lautrec, who (it has been surmised) suffered from the disease. In 1996, the defective gene responsible for Pycnodysostosis was located, offering accurate diagnosis, carrier testing and a more thorough understanding of this disorder. It is an autosomal recessive osteochondrodysplasia, usually diagnosed at an early age with incidence estimated to be 1.7 per 1 million births. Pycnodysostosis is a lysosomal storage disease of the bone caused by a mutation in the gene that codes the enzyme cathepsin K. The syndrome has been frequently reported in history. This article reports unusual ophthalmologic findings, conductive hearing loss due to suspected otosclerosis and sandal gap deformity in a Pycnodysostosis patient.

Highlights

He had frontal and bilateral parietal bossing .The sagittal, coronal and lambdoid sutures were separated and anterior and posterior fontanels were widely open
The parents of the child were offered an option for CTSK gene mutation testing for confirmation of diagnosis of pycnodysostosis, they refused for same in view of financial constraints as the same testing is not available currently in our country (India)
We suggest for active screening of all children diagnosed with pycnodysostosis for hearing defects and ophthalmological evaluation as similar evaluation was not seen previously in published literature

Summary

Discussion

Pycnodysostosis is an inherited disorder of the bone caused by a mutation in the gene that codes the enzyme cathepsin K This enzyme is important for normal bone cells called osteoclasts, to reabsorb into the bone and build new bone. The normal functioning of osteoclasts in individuals with pycnodysostosis is disrupted by a lack of cathepsin K, rendering individuals afflicted with this disorder to be unable to adequately reabsorb the component of bone called the organic matrix. The sclerosing activity of pycnodysostosis is due to a genetic defect located on chromosome 1q21 This anomaly consists of mutations that produce mutational changes in a lysosomal cystine protease, cathepsin K, the expression of which is reduced in the osteoclasts of these patients [2]. Dental hygiene and regular dental checkups are especially helpful for affected individuals due to various dental anomalies [10]

Conclusion

Findings

Elmore SM

Dormans J and Flynn J