A Novel Missense Mutation of NOG Interferes With the Dimerization of NOG and Causes Proximal Symphalangism Syndrome in a Chinese Family.

OBJECTIVES

NOG is an antagonist to bone morphogenetic proteins and plays an important role in proper bone and joint development. Dominant mutations in NOG may lead to a series of symphalangism spectrum disorders. In this study, we aimed to identify the genetic cause and the pathogenic mechanism of an autosomal dominant disorder with cosegregating proximal symphalangism and conductive hearing impairment in a Chinese family.

METHODS

Mutation screening of NOG was performed in the affected family members by polymerase chain reaction (PCR) amplification and direct sequencing. Western blotting analysis of NOG was performed in the leukocyte samples of the family members.

RESULTS

A novel p.W150C heterozygous mutation in NOG was identified cosegregating with the proximal symphalangism disorder in the family. Western blotting analysis showed that the p.W150C mutation interferes with the dimerization of the mutant NOG.

CONCLUSIONS

Our results agreed with previously published results of in vitro studies and suggested that impaired dimerization of mutant NOG is an important pathogenic mechanism for the NOG-related symphalangism spectrum disorder.