Maternally inherited hearing loss in a large kindred with a novel T7511C mutation in the mitochondrial DNA tRNA(Ser(UCN)) gene

Neurology. 1999 Jun 10;52(9):1905-8. doi: 10.1212/wnl.52.9.1905.


Thirty-six of 43 maternally related members of a large African American family experienced hearing loss. A muscle biopsy specimen from the proband showed cytochrome c oxidase (COX)-deficient fibers but no ragged-red fibers; biochemical analysis showed marked reduction of COX activity. A novel T7511C point mutation in the tRNA(Ser(UCN)) gene was present in almost homoplasmic levels (>95%) in the blood of 18 of 20 family members, and was also found in lower abundance in the other two. Single-fiber PCR showed that the mutational load was greater in COX-deficient muscle fibers. The tRNA(ser(UCN)) gene may be a "hot spot" for mutations associated with maternally transmitted hearing loss.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • DNA, Mitochondrial / genetics*
  • Deafness / genetics*
  • Female
  • Humans
  • Mothers*
  • Mutation
  • Pedigree
  • Polymerase Chain Reaction
  • Polymorphism, Restriction Fragment Length
  • RNA, Transfer, Ser / genetics*


  • DNA, Mitochondrial
  • RNA, Transfer, Ser