Genetic profile among children with congenital nonsyndromic hearing impairment: A study from a tertiary care centre in India

Vijay, Singh (2014) Genetic profile among children with congenital nonsyndromic hearing impairment: A study from a tertiary care centre in India. Masters thesis, Christian Medical College, Vellore.


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OBJECTIVE: To detect the percentage of GJB2 gene mutation in congenital non-syndromic hearing impaired children presenting at a tertiary care centre. METHODS: This is a pilot study conducted, 96 children were included in the study – 86 being retrospective. Children presenting with history of nonsyndromic sensorineural hearing impairment in the department of ENT of our hospital were enrolled in the study. . History was obtained based on information obtained by a combination of self-reporting and physician assessment. Clinical evaluation including physical examination, hearing evaluation, blood investigations including genetic test were done. Genetic test were done in Department of Clinical Genetics at CMC. RESULTS: In this study there were 96 probands, 36 males and 60 females. Among the probands 46 i.e. 47.9% had profound hearing loss. In our study we found Connexin 26 mutation in 13.5% of children with nonsyndromicsensorineural hearing loss. Out of the 36 boys, 19.4% had gjb2 mutation and 10% of the girls had that mutation however. In simple words, there is no evidence of association. We also found in our study all probands with GJB2 mutation had profound hearing loss. In our study we found 47% of GJB2 positive probands tested positive for W24X. 6.3% of the total probands tested positive for W24X mutation. Out of the total probands tested, 5.6% of males and 6.7% of females tested positive for W24X. We also found that all probands with W24X had profound hearing loss. In our study among the probands tested 38.5 % were born to consanguinous marriage. There are 37 of the children from consanguineous marriage of which 29.7% had GJB2 mutation and 3.4% out of nonconsanguineous had mutation and this difference was highly significant. Among probands born to consanguineous marriage, 62.2% had profound hearing loss as compared to 39% born to nonconsanguinous marriage. This study has shown that Connexin 26 mutation is less common in India than in western population. In our study nearly half of probands with GJB2 mutation were W24X positive and this is the commonest mutation in Indians. Nearly one third of consanguineous marriage with non-syndromicsensorineural hearing loss were GJB2 positive. In this study we also found that all children who were GJB2 positive had profound hearing loss. To conclude, genetic test have many benefits and most impotantly if found positive it helps in early intervention.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Hearing impairment ; GJB2 mutation ; W24X gene; RFLP ; congenital nonsyndromic hearing impairment ; genetic profile.
Subjects: MEDICAL > Otolaryngology
Depositing User: Devi S
Date Deposited: 13 Jul 2017 11:19
Last Modified: 24 Jun 2018 13:55

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