| Description: |
MERRF is a multisystem disease typically characterized by myoclonus as the first symptom, followed by epilepsy, ataxia, weakness, and dementia. Other common clinical features include hearing loss, short stature, optic atrophy, and cardiomyopathy with Wolff-Parkinson-White (WPW) syndrome. The disease is caused by mutations in mitochondrial DNA. The most common mutation that accounts for 80% of the MERRF cases is 8344A>G in the MTTK1 gene. Due to genetic and clinical heterogeneity and multisystem dysfunction, we highly recommend the screening test (see Mitochondrial DNA Screen (Point Mutations and Deletions)) for a patient suspected of MERRF, unless a specific mutation has already been detected in the family.
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