Phenotypic variants of the deafness-associated mitochondrial DNA A7445G mutation.
A number of nuclear and mitochondrial mutations have been implicated in non-syndromic hearing loss. Among them, various mutations of mitochondrial Ser(UCN)-tRNA and 12S rRNA genes have been found to be associated with deafness; the A7445G mitochondrial DNA (mtDNA) in this group is unique, simultaneously affecting two different mitochondrial genes, encoding the Ser(UCN)-tRNA and the first subunit of cytochrome oxidase. Besides the hearing loss, it is mainly associated with palmoplantar keratoderma, though; different phenotypic associations have been reported. The current paper reviews the available PubMed reports on the A7445G mtDNA mutation, with special attention to the phenotypic variations. Further, a Hungarian family with the A7445G mutation is reported, in which analysis of both the affected and the non-affected members revealed the mutation in both homo- and heteroplasmic forms, independently of the hearing status of the subjects, a phenomenon previously not reported in other pedigrees. The female lineage represented a rare variant of the U4b haplogroup.
Department of Medical Genetics and Child Development, University of Pécs, Pécs, Hungary.
Anita
A
Maász
Katalin
K
Komlósi
Kinga
K
Hadzsiev
Zsolt
Z
Szabó
Patrick J
PJ
Willems
Imre
I
Gerlinger
György
G
Kosztolányi
Károly
K
Méhes
Béla
B
Melegh
D004272:DNA, Mitochondrial / Q000235:genetics*; D003638:Deafness / Q000235:genetics* / Q000503:physiopathology*; D006801:Humans; D009154:Mutation / Q000235:genetics*; D010375:Pedigree; D010641:Phenotype
D004272:DNA, Mitochondrial