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Long‐term outcome of Leigh syndrome caused by the NARP‐T8993C mtDNA mutation
Author(s) -
Debray FrançoisGuillaume,
Lambert Marie,
Lortie Anne,
Vanasse Michel,
Mitchell Grant A.
Publication year - 2007
Publication title -
american journal of medical genetics part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.064
H-Index - 112
eISSN - 1552-4833
pISSN - 1552-4825
DOI - 10.1002/ajmg.a.31880
Subject(s) - term (time) , mitochondrial dna , outcome (game theory) , mutation , genetics , medicine , biology , economics , physics , gene , mathematical economics , quantum mechanics
Abstract Mutations at mitochondrial DNA (mtDNA) nucleotide 8993 can cause n eurogenic weakness, a taxia and r etinitis p igmentosa (NARP syndrome), or maternally inherited Leigh syndrome (LS), with a correlation between the amount of mutant mtDNA and the severity of the neurological disease. The T8993C mutation is generally considered to be clinically milder than the T8993G mutation but when the level of heteroplasmy exceeds 90%, progressive neurodegeneration has been found. We report on a long‐term follow‐up of a patient who presented at 4 years of age with typical LS but showed an unexpected resolution of his symptoms and a favorable outcome. At 18 years of age, his neurological examination was near normal, with neither peripheral neuropathy nor retinopathy. mtDNA analysis identified the presence of T8993C mutation at high level (>95%) in the patient's blood leukocytes. This case report and literature review emphasizes the variability of the phenotypic expression of the T8993C mutation and the need for caution in predictive counseling in such patients. © 2007 Wiley‐Liss, Inc.