MITOCHONDRIAL-DNA-8993 (NARP) MUTATION PRESENTING WITH A HETEROGENEOUS PHENOTYPE INCLUDING CEREBRAL-PALSY

The mitochondrial DNA (mtDNA) mutation 8993 is an important cause of L eigh's encephalopathy. A family is reported where other affected membe rs have presented with non-specific delayed development or cerebral pa lsy. The diagnosis should be considered not only in children with Leig h's encephalopathy, but also in those with mild neurological dysfuncti on (including cerebral palsy) if there is a pigmentary retinopathy or a family history of neurological or ophthalmological disease. There wa s some correlation in this family between the disease severity and the proportion of mutant mtDNA in the blood. This mutation appears to seg regate to high levels of mutant mtDNA rapidly within pedigrees and the mother of a severely affected child has a high risk of having further children with a high proportion of mutant mtDNA and a severe phenotyp e.