Dataset Information

A large homozygous deletion in the SAMHD1 gene causes atypical Aicardi-Goutieres syndrome associated with mtDNA deletions.

ABSTRACT: Aicardi-Goutiéres syndrome (AGS) is a genetic neurodegenerative disorder with clinical symptoms mimicking a congenital viral infection. Five causative genes have been described: three prime repair exonuclease1 (TREX1), ribonucleases H2A, B and C, and most recently SAM domain and HD domain 1 (SAMHD1). We performed a detailed clinical and molecular characterization of a family with autosomal recessive neurodegenerative disorder showing white matter destruction and calcifications, presenting in utero and associated with multiple mtDNA deletions. A muscle biopsy was normal and did not show any evidence of respiratory chain dysfunction. Southern blot analysis of tissue from a living child and affected fetuses demonstrated multiple mtDNA deletions. Molecular analysis of genes involved in mtDNA synthesis and maintenance (POLG?, POLG?, Twinkle, ANT1, TK2, SUCLA1 and DGOUK) revealed normal sequences. Sequencing of TREX1 and ribonucleases H2A, B and C failed to reveal any mutations. Whole-genome homozygosity mapping revealed a candidate region containing the SAMHD1 gene. Sequencing of the gene in the affected child and two affected fetuses revealed a large deletion (9 kb), spanning the promoter, exon1 and intron 1. The parents were found to be heterozygous for this deletion. The identification of a homozygous large deletion in the SAMHD1 gene causing atypical AGS with multiple mtDNA deletions may add information regarding the involvement of mitochondria in self-activation of innate immunity by cell intrinsic components.

SUBMITTER: Leshinsky-Silver E

PROVIDER: S-EPMC3062001 | biostudies-literature | 2011 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

A large homozygous deletion in the SAMHD1 gene causes atypical Aicardi-Goutiéres syndrome associated with mtDNA deletions.

Leshinsky-Silver Esther E Malinger Gustavo G Ben-Sira Liat L Kidron Dvora D Cohen Sarit S Inbar Shani S Bezaleli Tali T Levine Arie A Vinkler Chana C Lev Dorit D Lerman-Sagie Tally T

European journal of human genetics : EJHG 20101124 3

Aicardi-Goutiéres syndrome (AGS) is a genetic neurodegenerative disorder with clinical symptoms mimicking a congenital viral infection. Five causative genes have been described: three prime repair exonuclease1 (TREX1), ribonucleases H2A, B and C, and most recently SAM domain and HD domain 1 (SAMHD1). We performed a detailed clinical and molecular characterization of a family with autosomal recessive neurodegenerative disorder showing white matter destruction and calcifications, presenting in ute ...[more]

PMID: 21102625

Similar Datasets

Project description:IntroductionAicardi-Goutières Syndrome (AGS) is a rare encephalopathy with early onset that can be transmitted in both dominant and recessive forms. Its phenotypic covers a wide range of neurological and extraneurological symptoms. Nine genes that are all involved in nucleic acids (NAs) metabolism or signaling have so far been linked to the AGS phenotype. Recently, a link between autoimmune or neurodegenerative conditions and mitochondrial dysfunctions has been found. As part of the intricate system of epigenetic control, the mtDNA goes through various alterations. The displacement (D-loop) region represents one of the most methylated sites in the mtDNA. The term "mitoepigenetics" has been introduced as a result of increasing data suggesting that epigenetic processes may play a critical role in the control of mtDNA transcription and replication. Since we showed that RNASEH2B and RNASEH2A-mutated Lymphoblastoid Cell Lines (LCLs) derived from AGS patients had mitochondrial alterations, highlighting changes in the mtDNA content, the main objective of this study was to examine any potential methylation changes in the D-loop regulatory region of mitochondria and their relationship to the mtDNA copy number in peripheral blood cells of AGS patients with mutations in various AGS genes and healthy controls.Materials and methodsWe collected blood samples from 25 AGS patients and we performed RT-qPCR to assess the mtDNA copy number and pyrosequencing to measure DNA methylation levels in the D-loop region.ResultsComparing AGS patients to healthy controls, D-loop methylation levels and mtDNA copy number increased significantly. We also observed that in AGS patients, the mtDNA copy number increased with age at sampling, but not the D-loop methylation levels, and there was no relationship between sex and mtDNA copy number. In addition, the D-loop methylation levels and mtDNA copy number in the AGS group showed a non-statistically significant positive relation.ConclusionThese findings, which contradict the evidence for an inverse relationship between D-loop methylation levels and mtDNA copy number, show that AGS patients have higher D-loop methylation levels than healthy control subjects. Additional research is needed to identify the function of these features in the etiology and course of AGS.

Dataset Information

A large homozygous deletion in the SAMHD1 gene causes atypical Aicardi-Goutieres syndrome associated with mtDNA deletions.

Publications

A large homozygous deletion in the SAMHD1 gene causes atypical Aicardi-Goutiéres syndrome associated with mtDNA deletions.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets