Genetics of otosclerosis: finally catching up with other complex traits?

Otosclerosis is a relatively common cause of hearing impairment, characterized by abnormal bone remodeling of the middle and inner ear. In about 50-60% of the patients, the disease is present in a familial form. In most of these families, otosclerosis seems to be caused by a small number of genetic factors (oligogenic) while only in a small number of families the disease seems to be truly monogenic. In the remaining patients a complex genetic form of otosclerosis is present. Several studies have aimed to identify the genetic factors underlying otosclerosis, which has led to the identification of eight published loci for monogenic otosclerosis, as well as several genes and one chromosomal region (11q13.1) with a clear association with otosclerosis. Implementation of next-generation sequencing (NGS) in otosclerosis research has led to the identification of pathogenic variants in MEPE, ACAN and SERPINF1, although the pathogenic role of the latter is under debate. In addition, a recent GWAS can be considered a breakthrough for otosclerosis as it identified several strong associations with otosclerosis and suggested new potential candidate genes. These recent findings are important for unraveling the genetic architecture of otosclerosis. More future studies will help to understand the complete pathogenesis of the disease.