Prevalence of mitochondrial DNA mutations in childhood/congenital onset non-syndromal sensorineural hearing impairment
- aMolecular Medicine Unit, Clinical Sciences Building, St James's University Hospital, Beckett Street, Leeds LS9 7TF, UK, bDepartment of Clinical Genetics, Leicester Royal Infirmary, Leicester, UK, cCentre for Audiology, Education of the Deaf and Speech Pathology, University of Manchester, Manchester, UK, dInstitute of Child Health, University College London Medical School, London, UK, eDepartment of Clinical Genetics, St James's University Hospital, Leeds, UK
- Dr Hutchin,t.p.hutchin{at}leeds.ac.uk
- Revised 25 January 2001
- Accepted 30 January 2001
Abstract
Genetic factors are the major causes of childhood hearing impairment. Whereas autosomal recessive mutations account for the majority of prelingual non-syndromic sensorineural hearing impairment (NSSHI), the relative contribution of mitochondrial DNA (mtDNA) mutations to childhood onset NSSHI has not been established.
We screened 202 subjects with congenital/childhood onset NSSHI, consisting of 110 sporadic cases, 75 sib pairs, and 17 families with affected subjects in more than one generation, in order to determine the prevalence of mtDNA mutations associated with NSSHI.
mtDNA mutations were found in three of 10 families (30%) in whom the affected members were related through the maternal lineage. One sporadic case (0.9%) was also found to have a known mtDNA mutation but none was found in the sib pairs.
Although the prevalence of mtDNA mutations was low in the group as a whole (2%), we suggest that screening should be considered in cases of childhood hearing impairment when it is progressive and particularly in families where transmission is compatible with maternal inheritance.
