Syndromic Hearing Loss in Moroccan families is associated to homozygous missense variants in COL4A3 and MASP1

Syndromic hearing loss (SHL) represent a frequent origin of deafness worldwide. Aiming at improving the molecular diagnosis of SHL in Morocco, we analyzed two consanguineous families with Alport syndrome (AS) and Carnevale, Mingarelli, Malpuech, and Michels syndrome (3MC). Using whole exome sequencing, we identified two novel homozygous variants, the p.(Gly1385Arg) in COL4A3 in two siblings of the first family, and the p.(Gly476Arg) in MASP1 in the simplex case of the second family, respectively. Molecular modelling and stability analyses of the mutated proteins disclosed changes in the structure and destabilization of the wild-type structure. Our data, in the line with previous genetic analyses, illustrate the molecular variability of these two forms of SHL, and contribute to expand the molecular diagnosis of deafness in Morocco.