Clinical, Molecular, and Computational Analysis in two cases with mitochondrial encephalomyopathy associated with SUCLG1 mutation in a consanguineous family

Marwa Maalej; Amel Tej; Jihène Bouguila; Samia Tilouche; Senda Majdoub; Boudour Khabou; Mouna Tabbebi; Rahma Felhi; Marwa Ammar; Emna Mkaouar-Rebai; Leila Keskes; Lamia Boughamoura; Faiza Fakhfakh

doi:10.1016/j.bbrc.2017.12.011

Clinical, Molecular, and Computational Analysis in two cases with mitochondrial encephalomyopathy associated with SUCLG1 mutation in a consanguineous family

Biochem Biophys Res Commun. 2018 Jan 8;495(2):1730-1737. doi: 10.1016/j.bbrc.2017.12.011. Epub 2017 Dec 5.

Authors

Affiliations

¹ Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, University of Sfax, Tunisia; Laboratory of Human Molecular Genetics, Faculty of Medicine of Sfax, University of Sfax, Tunisia. Electronic address: marwamaalej7@gmail.com.
² Service de pédiatrie, C.H.U. Farhat Hachad de sousse, University of Sousse, Tunisia.
³ Service de Radiologie, CHU Farhat Hached, Sousse, University of Sousse, Tunisia.
⁴ Laboratory of Human Molecular Genetics, Faculty of Medicine of Sfax, University of Sfax, Tunisia.
⁵ Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, University of Sfax, Tunisia.
⁶ Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, University of Sfax, Tunisia. Electronic address: faiza.fakhfakh02@gmail.com.

PMID: 29217198
DOI: 10.1016/j.bbrc.2017.12.011

Abstract

Deficiency of the mitochondrial enzyme succinyl COA ligase (SUCL) is associated with encephalomyopathic mtDNA depletion syndrome and methylmalonic aciduria. This disorder is caused by mutations in both SUCL subunits genes: SUCLG1 (α subnit) and SUCLA2 (β subnit). We report here, two Tunisian patients belonging to a consanguineous family with mitochondrial encephalomyopathy, hearing loss, lactic acidosis, hypotonia, psychomotor retardation and methylmalonic aciduria. Mutational analysis of SUCLG1 gene showed, for the first time, the presence of c.41T > C in the exon 1 at homozygous state. In-silico analysis revealed that this mutation substitutes a conserved methionine residue to a threonine at position 14 (p.M14T) located at the SUCLG1 protein mitochondrial targeting sequence. Moreover, these analysis predicted that this mutation alter stability structure and mitochondrial translocation of the protein. In Addition, a decrease in mtDNA copy number was revealed by real time PCR in the peripheral blood leukocytes in the two patients compared with controls.

Keywords: SUCLG1; Succinyl COA ligase; mtDNA copy number.

Publication types

Case Reports
Research Support, Non-U.S. Gov't

MeSH terms

Acidosis, Lactic / genetics
Amino Acid Metabolism, Inborn Errors / genetics
Amino Acid Substitution
Child, Preschool
Consanguinity
DNA, Mitochondrial / genetics
Enzyme Stability / genetics
Female
Gene Dosage
Hearing Loss / genetics
Homozygote
Humans
Infant
Male
Mitochondrial Encephalomyopathies / enzymology*
Mitochondrial Encephalomyopathies / genetics*
Muscle Hypotonia / genetics
Mutation, Missense*
Succinate-CoA Ligases / chemistry
Succinate-CoA Ligases / deficiency*
Succinate-CoA Ligases / genetics*

Substances

DNA, Mitochondrial
SUCLG1 protein, human
Succinate-CoA Ligases

Supplementary concepts

Methylmalonic acidemia