Hearing impairment is common in various phenotypes of the mitochondrial DNA XXXX mutation.

@entity1 @entity20066 @entity296 @entity2749 @entity6 @entity3055 @entity75 @entity17903 @entity8193 @entity4610 @entity27379 @entity3148 @entity23355 @entity121 @entity393
OBJECTIVE: To determine whether there are common symptoms within different phenotypes of the mitochondrial DNA @entity23355 mutation. DESIGN: A series of 52 adults with mitochondrial @entity17903 and their symptomatic relatives were screened for the @entity23355 mutation using restriction enzyme analysis. In addition to clinical examination, @entity1 with the mutation underwent audiometry. RESULTS: The @entity23355 mutation was identified in 16 @entity1 (10 index @entity1 and 6 symptomatic relatives). Six of these @entity1 presented with strokelike episodes and met the classical criteria of @entity20066 ( @entity3055 , @entity75 , @entity8193 , @entity2749 ), and one had @entity20066 / @entity27379 ( @entity3148 with ragged-red fibers) overlap syndrome. Two @entity1 presented with strokelike episodes but did not meet the classical criteria of @entity20066 . Predominant features of the 8 other @entity1 were @entity121 with @entity393 and @entity6 (n = 1), chronic progressive external @entity4610 (n = 1), @entity6 with @entity393 (n = 1), painful @entity121 with @entity393 (n = 1), @entity296 (n = 1), @entity6 (n = 1), and @entity393 (n = 2). In 11 of 16 @entity1 , @entity393 was obvious on clinical examination. Furthermore, all 5 @entity1 with normal hearing on clinical examination showed subclinical @entity393 ; in 4, @entity393 was more pronounced than age-related @entity393 and in 1, @entity393 can be age related as well. CONCLUSIONS: A variety of phenotypes represent the variable multisystemic involvement of the @entity23355 mutation. Less than half of the @entity1 presented with @entity20066 . Hearing impairment, the most common symptom, was clinically or subclinically relevant in 15 (94%) of 16 @entity1 .
