Case Report: Rare Homozygous RNASEH1 Mutations Associated With Adult-Onset Mitochondrial Encephalomyopathy and Multiple Mitochondrial DNA Deletions.

ABSTRACT: Mitochondrial DNA (mtDNA) maintenance disorders embrace a broad range of clinical syndromes distinguished by the evidence of mtDNA depletion and/or deletions in affected tissues. Among the nuclear genes associated with mtDNA maintenance disorders, RNASEH1 mutations produce a homogeneous phenotype, with progressive external ophthalmoplegia (PEO), ptosis, limb weakness, cerebellar ataxia, and dysphagia. The encoded enzyme, ribonuclease H1, is involved in mtDNA replication, whose impairment leads to an increase in replication intermediates resulting from mtDNA replication slowdown. Here, we describe two unrelated Italian probands (Patient 1 and Patient 2) affected by chronic PEO, ptosis, and muscle weakness. Cerebellar features and severe dysphagia requiring enteral feeding were observ

SUBMITTER: Manini A 

PROVIDER: S-EPMC9194440 | biostudies-literature | 2022

REPOSITORIES: biostudies-literature