Maternally-inherited Leigh syndrome (MILS)
Incidence
It is a mtDNA point mutation. MILS is associated with mutations in the ATPase 6 gene (subunit 6 of complex V) with mitochondrial heteroplasmy > than 90%.. Maternal inheritance.
Clinical Characteristics
MILS is a multisystem degenerative encephalopathy with onset in infancy, characterized by hypotonia, myoclonus, brainstem dysfunction, peripheral neuropathy, developmental delay, psychomotor regression, ataxia, seizures and optic atrophy. It present characteristic pathological findings of symmetric necrotic foci in the thalamus, basal ganglia, brainstem and dentate nuclei. In addition, retinitis pigmentosa is present in 50% of MILS patients. Ragged-red fibers (RRF) are absent but electronic microscopy (EM) of muscle biopsy has revealed small subsarcolemmal aggregates of mitochondria with abnormal cristae. Muscle fibers are COX-positive, but a subset of fibers may be either negative or deficient for mitochondrial ATPase.
Precipitants
no
Provocation Tests
no
Diagnostic Procedures
DB-W, DB-F (DNA testing for point mutation)