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Neurology. 2014 Jun 10;82(23):2063-71. doi: 10.1212/WNL.0000000000000497. Epub 2014 May 7.

Novel (ovario) leukodystrophy related to AARS2 mutations.

Author information

1
From the Department of Life Sciences (C.D., E.B., I.F.), University of Parma; Unit of Molecular Neurogenetics (D.D., L.M., C.L., D.G.), SOSD Genetics of Neurodegenerative and Metabolic Diseases (C.M.), and Departments of Clinical Neurosciences (E.S.) and Neuroradiology (M.S.), Fondazione Istituto Neurologico Carlo Besta, Istituto di Ricovero e Cura a Carattere Scientifico, Milan, Italy; Department of Child Neurology (S.H.K., E.M.H., T.E.M.A., N.I.W., M.S.v.d.K.), Department of Clinical Chemistry, Metabolic Unit (G.S.S.), Neuroscience Campus Amsterdam, and Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (M.S.v.d.K.), VU University Medical Center, Amsterdam, the Netherlands; Institute of Human Genetics (T.B.H., T.M.S., T.M., H.P.), Technical University, Munich; Institute of Human Genetics (T.B.H., T.M.S., T.M., H.P.), Helmholtz Zentrum Munich, Neuherberg, Germany; Department of Molecular and Human Genetics (L.-J.W.), Baylor College of Medicine, Houston, TX; Department of Genetics (K.C.), and Center for Genetic Medicine Research, Department of Neurology (A.V.), Children's National Medical Center, Washington, DC; Department of Clinical Genetics (A.C.), Liverpool Hospital, Sydney, Australia; Neurology Department (H.R.), Centro Hospitalar São João, and Department of Clinical Neuroscience and Mental Health, Faculty of Medicine, University of Porto, Portugal; Medical Genetics Center (K.Ő.), United Laboratories, Tartu University Clinics, Estonia; Institute of Metabolic Disease (R.S.), Baylor Research Institute, Dallas, TX; and Mitochondrial Biology Unit-MRC (M.Z.), Cambridge, UK.
2
From the Department of Life Sciences (C.D., E.B., I.F.), University of Parma; Unit of Molecular Neurogenetics (D.D., L.M., C.L., D.G.), SOSD Genetics of Neurodegenerative and Metabolic Diseases (C.M.), and Departments of Clinical Neurosciences (E.S.) and Neuroradiology (M.S.), Fondazione Istituto Neurologico Carlo Besta, Istituto di Ricovero e Cura a Carattere Scientifico, Milan, Italy; Department of Child Neurology (S.H.K., E.M.H., T.E.M.A., N.I.W., M.S.v.d.K.), Department of Clinical Chemistry, Metabolic Unit (G.S.S.), Neuroscience Campus Amsterdam, and Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (M.S.v.d.K.), VU University Medical Center, Amsterdam, the Netherlands; Institute of Human Genetics (T.B.H., T.M.S., T.M., H.P.), Technical University, Munich; Institute of Human Genetics (T.B.H., T.M.S., T.M., H.P.), Helmholtz Zentrum Munich, Neuherberg, Germany; Department of Molecular and Human Genetics (L.-J.W.), Baylor College of Medicine, Houston, TX; Department of Genetics (K.C.), and Center for Genetic Medicine Research, Department of Neurology (A.V.), Children's National Medical Center, Washington, DC; Department of Clinical Genetics (A.C.), Liverpool Hospital, Sydney, Australia; Neurology Department (H.R.), Centro Hospitalar São João, and Department of Clinical Neuroscience and Mental Health, Faculty of Medicine, University of Porto, Portugal; Medical Genetics Center (K.Ő.), United Laboratories, Tartu University Clinics, Estonia; Institute of Metabolic Disease (R.S.), Baylor Research Institute, Dallas, TX; and Mitochondrial Biology Unit-MRC (M.Z.), Cambridge, UK. ms.vanderknaap@vumc.nl dghezzi@istituto-besta.it.

Abstract

OBJECTIVES:

The study was focused on leukoencephalopathies of unknown cause in order to define a novel, homogeneous phenotype suggestive of a common genetic defect, based on clinical and MRI findings, and to identify the causal genetic defect shared by patients with this phenotype.

METHODS:

Independent next-generation exome-sequencing studies were performed in 2 unrelated patients with a leukoencephalopathy. MRI findings in these patients were compared with available MRIs in a database of unclassified leukoencephalopathies; 11 patients with similar MRI abnormalities were selected. Clinical and MRI findings were investigated.

RESULTS:

Next-generation sequencing revealed compound heterozygous mutations in AARS2 encoding mitochondrial alanyl-tRNA synthetase in both patients. Functional studies in yeast confirmed the pathogenicity of the mutations in one patient. Sanger sequencing revealed AARS2 mutations in 4 of the 11 selected patients. The 6 patients with AARS2 mutations had childhood- to adulthood-onset signs of neurologic deterioration consisting of ataxia, spasticity, and cognitive decline with features of frontal lobe dysfunction. MRIs showed a leukoencephalopathy with striking involvement of left-right connections, descending tracts, and cerebellar atrophy. All female patients had ovarian failure. None of the patients had signs of a cardiomyopathy.

CONCLUSIONS:

Mutations in AARS2 have been found in a severe form of infantile cardiomyopathy in 2 families. We present 6 patients with a new phenotype caused by AARS2 mutations, characterized by leukoencephalopathy and, in female patients, ovarian failure, indicating that the phenotypic spectrum associated with AARS2 variants is much wider than previously reported.

PMID:
24808023
PMCID:
PMC4118500
DOI:
10.1212/WNL.0000000000000497
[Indexed for MEDLINE]
Free PMC Article

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