Per GeneReviews: "Deafness-infertility syndrome (DIS) is caused by an autosomal recessive contiguous gene deletion at chromosome 15q15.3 including the genes CATSPER2 and STRC (Stereocilin). In all cases of DIS resulting from the CATSPER2-STRC deletion, the entire CATSPER2 gene is deleted [Avidan et al 2003, Zhang et al 2007]. It is unclear whether nonsense or missense mutations in CATSPER2 would lead to a nonsyndromic male infertility phenotype". It is generally well accepted that loss of STRC causes the deafness phenotype and loss of CATSPER2 causes the male infertility phenotype.