Molecular genetic testing is useful to differentiate syndromic stapes ankylosis from otosclerosis, and even mild skeletal anomalies can be a diagnostic indicator of NOG-associated disease.
Haploinsufficiency of NOG gene has been implicated in the development of conductive hearing loss, skeletal anomalies including symphalangism, contractures of joints, and hyperopia in our patient and may also contribute to the development of tracheo-esophageal fistula and/or esophageal atresia.
Autosomal dominant stapes ankylosis with broad thumbs and toes, hyperopia, and skeletal anomalies is caused by heterozygous nonsense and frameshift mutations in NOG, the gene encoding noggin.