What causes hearing impairment in babies and children?
Hearing impairment can be inherited (genetic) or nongenetic. Nongenetic causes include illness or injury occurring before, during or after birth. In some cases, the cause of hearing impairment is not known. About 90 percent of babies with congenital hearing impairment are born to hearing parents (1). Genetic factors are believed to cause 33 percent of cases of hearing impairment in infants and young children (1). Scientists believe that mutations (changes) in as many as 400 genes may contribute to hearing impairment (1). Genetic causes (1) of hearing impairment can be: • Syndromatic: One feature of a group of birth defects that occur together. This type of impairment accounts for about 30 percent of cases. • Nonsyndromatic: A solitary birth defect. About 30 percent of cases of nonsyndromatic hearing impairment are caused by a mutation in a gene called Connexin 26.About one-third of cases of hearing impairment are caused by nongenetic factors (1). They include illnesses during pregnancy
