NTN4 and Menkes disease: Previous studies have shown that there is an enrichment of rare missense variants in some genes related to hearing loss, such as: GJB2, USH1G, SLC26A, USH1G, ESRRB, and CLDN14, as well as in some genes implicated in the “axonal guidance signaling” signaling pathway such as NTN4 and NOX3, in patients with sporadic MD [19].