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myopathic mitochondrial DNA depletion syndrome
Clinically heterogeneous group of disorders
Pathology:
- reduction in mitochondrial DNA (mtDNA) copy number
- may affect single organs, typically muscle or liver, or multiple tissues
- myopathic form: 66-86% mtDNA depletion
- hepatocerebral form: 99% mtDNA depletion in liver
Genetics:
- autosomal recessive
- reduction in mitochondrial DNA (mtDNA) copy number
- deletion of SUCLA2 is associated with encephalomyopathy
- defects in RRM2B are associated with encephalomyopathy with renal tubulopathy
- associated with defects in TK2
- associated with defects in DGUOK (type 3)
Clinical manifestations:
- various combinations of hypotonia, tubulopathy, seizures, respiratory distress, diarrhea
- myopathic form is slowly progressive, starting in childhood
- hepatocerebral form is presumably more severe
Laboratory:
- lactate in plasma
- lactic acidosis is seen in patients with defects in RRM2B or DGUOK [type 3]
- MT-TK gene mutation
Specific
mitochondrial DNA depletion syndrome 11
mitochondrial DNA depletion syndrome type 3
General
mitochondrial encephalomyopathy
Database Correlations
OMIM correlations
References
- UniProt :accession Q9P2R7
- UniProt :accession Q7LG56