COL2A1 and hearing loss disorder: Among these 46 patients, homozygous or heterozygous GJB2:c.109G>A was mostly prevalent, together with other variants associated with progressive, late-onset hearing loss (COL11A1, GJB2:c.235del, KCNQ4, MAF, and SLC26A4) or syndromes partially characterized by hearing loss (COL11A1, COL2A1, CREBBP, FLNA, and PTPN11).