MCM2 mutation causes autosomal dominant nonsyndromic hearing loss (DFNA70): novel variant in the second family.

ABSTRACT

Pathogenic variants in MCM2 could result in mild to severe sensorineural hearing loss in the affected individuals (deafness, autosomal dominant 70; DFNA70; OMIM 616968), an extremely rare autosomal dominant progressive disorder. Here, we report a novel missense variant (NM_004526c.388C>T, p.R130C; Clinvar SCV002072508) in MCM2 in an Iranian family identified by whole-exome sequencing and confirmed by Sanger sequencing. The heterozygous variant (NM_004526c.388C>T, p.R130C) in MCM2 was identified in the proband and his mother. The proband is a nine-year-old male born to nonconsanguineous parents. The proband was characterized by nonsyndromic hearing loss, while his mother showed a mild form of the disorder. This study reports the second disease-causing variant in MCM2 in the world and confirms that hearing loss arising from variants in MCM2 is nonsyndromic. Nevertheless, as was reported in the previous family, phenotype could vary among the patients with the same variant.