Isolated late-onset cone-rod dystrophy revealing a familial neurogenic muscle weakness, ataxia, and retinitis pigmentosa syndrome with the T8993G mitochondrial mutation.
OBJECTIVE
To report a late-onset cone-rod dystrophy that revealed a familial neurogenic muscle weakness, ataxia, and retinitis pigmentosa syndrome as a consequence of the T8993G mitochondrial mutation.


METHODS
Observational case series. A 42-year-old female disclosed a late-onset retinal dystrophy. The family history revealed that her three sons, one of them deceased at the age of 4, had mental and neurologic impairment of variable severity. The retinal dystrophy of the mother was classified as a cone-rod dystrophy. Retinal dystrophy was subsequently diagnosed in the two surviving sons. Screening for mutation in the mitochondrial DNA (mtDNA) was performed because of the combination of neurologic involvement and retinal dystrophy in this family.


RESULTS
Molecular analysis of the mtDNA revealed the ATPase-6 gene T8993G mutation in the mother and the two sons.


CONCLUSIONS
This family illustrates the remarkably variable expression of retinal and systemic manifestations related to the T8993G mutation ranging from an isolated late-onset cone-rod dystrophy to a severe neurodegenerative process with a dramatic outcome. Genetic counseling for retinal dystrophies requires careful evaluation of the familial medical history.
Porto
F B
FB
Ophthalmologic Clinic, University Hospitals of Strasbourg, 1 Place de l'Hôpital, 67091 Strasbourg Cedex, France.
Mack
G
G
Sterboul
M J
MJ
Lewin
P
P
Flament
J
J
Sahel
J
J
Dollfus
H
H
D000251:Adenosine Triphosphatases / Q000235:genetics; D000328:Adult; D001259:Ataxia / Q000175:diagnosis / Q000235:genetics*; D002675:Child, Preschool; D004252:DNA Mutational Analysis; D004272:DNA, Mitochondrial / Q000235:genetics*; D004596:Electroretinography; D005260:Female; D006801:Humans; D008297:Male; D008928:Mitochondria / Q000235:genetics; D017240:Mitochondrial Myopathies / Q000175:diagnosis / Q000235:genetics*; D018908:Muscle Weakness / Q000175:diagnosis / Q000235:genetics*; D010375:Pedigree; D020419:Photoreceptor Cells, Vertebrate / Q000473:pathology*; D017354:Point Mutation; D012162:Retinal Degeneration / Q000175:diagnosis / Q000235:genetics*; D012174:Retinitis Pigmentosa / Q000175:diagnosis / Q000235:genetics*; D013577:Syndrome
D004272:DNA, Mitochondrial; D000251:Adenosine Triphosphatases