Supplementary Material for: A Novel Synonymous Homozygous c.2904G>A Mutation in the MYO7A Gene Associated with Severe Deafness and Myopia Syndrome： A Case Report in a Chinese Family

Introduction Deafness and myopia syndrome is a rare hereditary disease caused by gene mutations. Here, we present a boy with early-onset bilateral profound sensorineural hearing loss and high myopia, which is associated with a homozygous MYO7A c.2904G>A variant. Case presentation The proband is a boy without a family history of hereditary disease who was diagnosed with bilateral moderate to severe hearing impairment (threshold of 110db) when he was 18 months old. He was later diagnosed as having myopia at the age of 3 years 2 months with 600 degrees (-6 DS in both eyes). Genetic studies found heterozygous c.270delA (p.Asp91Ilefs*10) and c.1627G>A (p.Gly543Arg) mutations in TRPM1, heterozygous c.404C>T (p.Ser135Leu) variant in SLC39A5, and the homozygous c.2904G>A (p.Glu968Glu) variant in MYO7A. The TRPM1 and SLC39A5 mutations were from his father, while the c.2904G>A mutation in MYO7A was inherited from both parents. Advanced Bionics CI model 90k1j (processor Naida Q30) bilateral cochlear implantation was carried out. The postoperative results were good, and the proband is currently in a mainstream elementary school with normal ophthalmic follow-up, which does not show retinal abnormalities. Conclusion The MYO7A c.2904G>A variant is probably linked with the deafness and myopia syndrome presented by the proband, and it is inherited in an autosomal recessive pattern. These findings underscore the importance of early clinical intervention, comprehensive phenotyping, and genetic testing in diagnosing rare sensory disorders, even in the absence of a family history.