Abstract

  The POLG gene is responsible for production of alpha subunit, of a protein called polymerase gamma (pol γ). Pol γ is a mitochondrial DNA polymerase, responsible for replication of the mitochondrial genome. POLG-related disorders comprise a continuum of broad and overlapping phenotypes that can be distinct clinical entities or consist of a spectrum of overlapping phenotypes. Presentations within a given family are usually similar. Although almost any organ system can be involved, evidence to date suggests that diabetes and cardiomyopathy are not very common in POLG-related disorders, distinguishing them from other multisystem mitochondrial diseases. Mutations in POLG can cause early childhood mitochondrial DNA (mtDNA) depletion syndromes or later- onset syndromes arising from mt DNA deletions. POLG mutations are the most common cause of inherited mitochondrial disorders, with as many as 2% of the population carrying these mutations. Clinical features may include hypotonia, developmental delay, seizures, movement disorder (e.g., myoclonus, dysarthria, choreoathetosis, parkinsonism), Myopathy(e.g., ptosis, ophthalmoplegia, proximal > distal limb weakness with fatigue and exercise intolerance), Ataxia, Peripheral neuropathy, Episodic psychomotor regression, Psychiatric illness (e.g., depression, mood disorder),Endocrinopathy (e.g., premature ovarian failure).Most common disorders caused by POLG mutations are Alpers-Hutten ocher syndrome (AHS),Childhood myocerebrohepatopathy spectrum(MCHS),Myoclonic epilepsy myopathy sensory ataxia (MEMSA),Ataxia neuropathy spectrum (ANS),Autosomal recessive progressive external ophthalmoplegia (arPEO), Autosomal dominant progressive external ophthalmoplegia (adPEO). This review will summarize POLG related disorders and their mimics focusing mainly on the neurological manifestations of these conditions.

Keywords: POLG; Mimics; Mitochondrial DNA; mtDNA polymerase; Syndromes

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Citation

Citation: Rajib Dutta. “POLG Related Neurological Disorders and Their Mimics".Acta Scientific Neurology 3.2 (2020): 54-59.

Copyright

Copyright: © 2020 Rajib Dutta. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.