GJB2 and Alzheimer disease: Here, we found that, for many of the studied genes, the carrier frequencies for some of the most common recessive disorders, such as GJB2-related DFNB1 nonsyndromic hearing loss and deafness, citrullinemia argininosuccinate synthase deficiency, late-onset Alzheimer disease, and AR intellectual disability, are higher than that previously reported (26–29).