Sco2 Protein Deficiency-Based Mitochondrial Encephalomyopathy with the SMA-like Picture of Neurogenic Muscle Atrophy - Case Reports
Abstract
Various mitochondrial diseases with clinical, electromyographical and histological signs imitating spinal muscular atrophy ("SMA-like diseases") with no detected mutation in SMN1 gene have been described in recent years. Respiratory chain disorder was considered due to broad impairment of the central and peripheral nervous systems (encephalopathy, neuropathy) and other tissue and organ involvement (cardiomyopathy, myopathy, hepatopathy).
The number of previously-reported mitochondrial syndromes with "SMA-like" sign development is limited. Revealing the phenotype in a detailed clinical context may lead to targeted molecular-genetic analysis and specific diagnostics without calling upon other investigations.
A typical representative of this syndrome group is mitochondrial encephalopathy with cardiomyopathy and lactic acidosis arising out of a mutation in gene coding protein Sco2 protein, which is involved in the assembly of mitochondrial cytochrome c oxidase. Two case histories are presented, of patients in whom SMA-like phenotype development led to SCO2 gene investigation and correct diagnosis.