What type of inheritance pattern is most common in Nonsyndromic hearing loss and deafness?

Nonsyndromic hearing loss and deafness often demonstrate an autosomal recessive inheritance pattern, which is the most prevalent form associated with this condition. In this type of inheritance, an individual must inherit two copies of the mutated gene, one from each parent, in order to express the phenotype of hearing loss or deafness.

Approximately 50%-70% of nonsyndromic hearing loss cases are attributed to mutations in genes that follow this autosomal recessive pattern. Notably, mutations in the GJB2 gene, which encodes the protein connexin 26, are among the most frequently implicated in this form of hearing loss. As both parents typically carry one copy of the mutated gene but do not exhibit symptoms themselves, the likelihood of having a child with hearing loss increases when both parents are carriers.

Other inheritance patterns exist, such as autosomal dominant, where only one copy of a mutated gene can lead to the condition; however, this is less common in nonsyndromic cases. X-linked dominant and mitochondrial inheritance also have distinct phenomenology and prevalence rates, but they are not predominant in nonsyndromic hearing loss, further solidifying why autosomal recessive is recognized as the most common pattern for this specific condition.