Journal: Molecular Genetics and Metabolism Reports
Publication Date: October 3, 2020
Introduction: Pathogenic variants in SURF1, a nuclear-encoded gene encoding a mitochondrial chaperone involved in COX assembly, are one of the most common causes of Leigh syndrome (LS).
Material-Methods: Sixteen patients diagnosed to have SURF1-related LS between 2012-2020 were included in the study. Their clinical, biochemical and molecular findings were recorded. 10⁄16 patients were diagnosed using whole exome sequencing (WES), 4⁄16 by Sanger sequencing of SURF1, 1⁄16 via targeted exome sequencing and 1⁄16 patient with whole genome sequencing (WGS). The pathogenicity of SURF1 variants was evaluated by phylogenetic studies and modeling on the 3D structure of the SURF1 protein.
Results: We identified 16 patients from 14 families who were either homozygous or compound heterozygous for SURF1 mutations. Nine different SURF1 mutations were detected The C.769G>A was the most common mutation with an allelic frequency of 33.3% (8⁄24), c.870dupT [(p.Lys291*); (4⁄24 16.6%)], c.169delG [(p.Glu57Lysfs*15), (2⁄24; 8.3%)], c.532T>A [(p.Tyr178Asn); (2⁄24, 8.3%)], c.653_654delCT [(p.Pro218Argfs*29); (2⁄24, 8.3%)] c.595_597delGGA [(p.Gly199del); (1⁄24, 4.1%)], c.751+1G>A (1⁄24, 4.1%), c.356C>T [(p.Pro119Leu); (2⁄24, 8.3%)] were the other detected variants. Two mutations, C.595_597delGGA and c.356C> T, were detected for the first time. The c.769 G> A mutation detected in 6 patients from 5 families was evaluated in terms of phenotype-genotype correlation. There was no definite genotype – phenotype correlation.
Conclusions: To date, more than 120 patients of LS with SURF1 mutations have been reported. We shared the clinical, molecular data and natural course of 16 new SURF1 defect patients from our country. This study is the first comprehensive research from Turkey that provides information about disease-causing variants in the SURF1 gene. The identification of common variants and phenotype of the SURF1 gene is important for understanding SURF1 related LS.