Phenotypic variations in patients with linker-region mutations in the mitochondrial DNA polymerase gamma gene

Background: We studied three patients with evidence of mitochondrial disease for mutations in the nuclear mitochondrial DNA (mtDNA) polymerase gamma gene (POLG1). Two patients (pat.1, 2) presented with Alpers syndrome (refractory epilepsy, developmental delay, liver failure), while the third patient (pat. 3) had chronic progressive external ophthalmoplegia (CPEOplus) with first symptoms in early adulthood, but no liver involvement. Methods: Skeletal muscle biopsy with histological, biochemical, and moleculargenetic mtDNA examinations. Postmortem muscle and liver tissue investigations with histology and quantitat…