Causes of childhood deafness in Pukhtoonkhwa Province of Pakistan and the role of consanguinity

Abstract

Background: Deafness is the hidden disability of childhood, and leads to poor educational and employment prospects. There is little published information on deafness in Pakistan. Profound hearing impairment is more prevalent in countries where consanguineous marriages are common, such as Pakistan. This study aimed to assess causes of childhood deafness and association with parental consanguinity, within deaf and hearing children in the Peshawar district of Pukhtoonkhwa Province, Pakistan.Methods: One hundred and forty deaf children were identified from two schools for deaf children within the Peshawar district. These children were assessed via audiology, otoscopic examination, case note review and parental history, in order to attempt to ascertain the cause of their deafness. Two hundred and twenty-one attendees at a local immunisation clinic (taken as representative of the local childhood population) were also screened for hearing impairment. Parents of both groups of children were assessed by interview and questionnaire in order to ascertain the mother and father's family relationship (i.e. whether cousins or unrelated).Results: Of the 140 deaf school pupils, 92.1 per cent were profoundly hearing impaired and 7.9 per cent were severely hearing impaired. All these children had bilateral sensorineural hearing loss. A possible cause of deafness was identified in only six of these children. Parental consanguinity (i.e. first or second cousins) was established for 86.4 per cent of deaf school pupils and 59.7 per cent of immunisation clinic attendees. None of the control children were identified as having a hearing problem.Conclusion: The prevalence of parental consanguinity was significantly higher in deaf children compared with non-hearing impaired children. However, the study also confirmed a high rate of consanguinity within the general Peshawar community. In this setting, prevention of consanguineous unions is the only means of reducing levels of congenital hearing impairment. The current levels of hearing disability represent both a prominent public health problem and an important, potentially preventable childhood disability.

Follow-Up Results of Newborns after Hearing Screening at a Training and Research Hospital in Turkey

“…Consanguineous marriage is a custom that is commonly practiced among the African, Asian, and Latin American communities, whether they live in their own countries or are settled in USA or Europe. It is also common in Turkey, and many studies in Turkey and other countries have reported that the siblings of consanguineous marriages have a notably higher incidence of autosomal recessive diseases comprising hearing impairment [27][28][29][30][31] . Sajjad et al [28] conducted a study among 140 deaf school pupils and 221 non-hearing-impaired children in Pakistan.…”

“…It is also common in Turkey, and many studies in Turkey and other countries have reported that the siblings of consanguineous marriages have a notably higher incidence of autosomal recessive diseases comprising hearing impairment [27][28][29][30][31] . Sajjad et al [28] conducted a study among 140 deaf school pupils and 221 non-hearing-impaired children in Pakistan. They found that parental consanguinity (i.e., first and second cousins) constituted 86.4% of deaf school children and 59.7% of non-hearing-impaired children.…”

Consanguinity and hearing impairment in a deaf school

“…Various other studies conducted amongst children born to consanguineous parents reveal a much higher incidence of hearing loss in this group. 9,10,11 This study also reveals a family history of deafness in 22. 0%, this is supported by the study J.O.…”

“…Particularly in the Muslim community, 20-50 percent of all marriages are consanguineous. 11 The most recent consanguinity estimate indicated that some 10.4% of the world population are either married to a biological relative or are the progeny of a consanguineous union. There is no prescription that Muslims marry within the family, and first cousin marriage is freely permissible in the Jewish, Christian protestant, Buddhist and Zoroastrian / parsi religions.…”

Deafness Genes in Israel: Implications for Diagnostics in the Clinic

“…Nonsyndromic deafness affects approximately 1 in 1000 newborns and 4% of people aged younger than 45 y (1). This number rises dramatically in regions where consanguinity is an acceptable social custom and is encouraged (2,3). Progressive HL affects an even greater proportion of the population.…”