A set of disorders characterized by multiple mitochondrial DNA (mtDNA) deletions in skeletal muscle, in which the clinical features are adult onset of weakness of the external eye muscles and exercise intolerance. Additional symptoms are variable. Autosomal dominant progressive external ophthalmoplegia (adPEO) with mtDNA deletions-1 (PEOA1) is caused by mutation in the nuclear-encoded DNA polymerase-γ gene, as is an autosomal recessive form ( PEOB1). PEOA2 is caused by mutation in the adenine nucleotide translocator (ANT) gene; PEOA3 by mutation in the twinkle gene; PEOA4 by mutation in the nuclear-encoded DNA polymerase-γ2 gene (POLG2).
Subjects: Medicine and Health.