Some are born deaf because of a spontaneous genetic mutation; some are due to the gene for deafness being very dominant in their families. There are many villages around the world that have high rates of deafness. What intensified this situation is that in many of the villages the majorities of the members are carriers of the gene and keep marrying one another, passing on the gene. Even though they are called “all-deaf” villages, it is literally far from the truth. No village can be all deaf; the title is in reference to the village having a deaf majority.
Read on at https://deafniche.com/8deaf-villages-around-world