Sensorineural hearing impairment is a common feature of consanguineous marriage

الملخص EN

Introduction : Sensor neural hearing loss (SNHL) accounts for about 60 % of all hearing loss.

This is sometimes also called "Nerve deafness".

The term "Sensor neural" is used to indicate that there is either a cochlear or an eight nerve lesion.

The diagnosis of sensor neural hearing loss is made through audiometry, which shows a significant hearing loss without "The air-bone gap" that, is characteristic of conductive hearing disturbances.

Among various risk factors described for deafness, consanguinity is an established high risk.

Aim of the Work : this work was carried out to study the prevalence of sensor neural hearing loss in offspring's of consanguineous marriage, who attended the Medical Genetics Center, Ain Shams University.

Patients and Methods : The study was performed on 950 children with congenital hearing loss.

Results : Consanguineous marriage was present in 71.2 % of studied cases.

47.3 % of these cases, parents were 1] st cousin, in 36.7 % parents were 2nd cousin, 16 % had remote consanguinity.

28.8 % of cases were the offspring of non-consanguineous marriage.

Also, the results showed that 44.2 % of cases had severe degree of sensor neural hearing loss (71-90 dBHL), 24.3% had profound hearing loss (> 90 dBHL).

Autosomal dominant inheritance (AD) hearing loss was detected in 40 % of cases.

Autosomal recessive inheritance hearing loss was discovered in 27 % of cases, and in 18.7 % of study cases the hearing loss was associated with genetic syndromes, where 88.8 % of these cases were associated with Down syndrome.

Conclusion : the incidence of hereditary hearing impairment is commoner in developing countries compared to developed countries, so, prevention is essential to reduce the incidence of genetic hearing loss.

Premarital and antenatal screening should be applied whenever possible, at least for those at risk of developing genetic diseases including hearing impairment.