title: Deleterious mutation in FDX1L gene is associated with a novel mitochondrial muscle myopathy.
abstract: Isolated metabolic myopathies encompass a heterogeneous group of disorders, with mitochondrial myopathies being a subgroup, with depleted skeletal muscle energy production manifesting either by recurrent episodes of myoglobinuria or progressive muscle weakness. In this study, we investigated the genetic cause of a patient from a consanguineous family who presented with adolescent onset autosomal recessive mitochondrial myopathy. Analysis of enzyme activities of the five respiratory chain complexes in our patients' skeletal muscle showed severely impaired activities of iron sulfur (Fe-S)-dependent complexes I, II and III and mitochondrial aconitase. We employed exome sequencing combined with homozygosity mapping to identify a homozygous mutation, c.1A>T, in the FDX1L gene, which encodes the mitochondrial ferredoxin 2 (Fdx2) protein. The mutation disrupts the ATG initiation translation site resulting in severe reduction of Fdx2 content in the patient muscle and fibroblasts mitochondria. Fdx2 is the second component of the Fe-S cluster biogenesis machinery, the first being IscU that is associated with isolated mitochondrial myopathy. We suggest adding genetic analysis of FDX1L in cases of mitochondrial myopathy especially when associated with reduced activity of the respiratory chain complexes I, II and III.
authors.affiliation: 1] Department of Pediatric A', Emek Medical Center, Afula, Rappaport School of Medicine, Technion, Haifa, Israel [2] Genetic Institute, Emek Medical Center, Afula, Rappaport School of Medicine, Technion, Haifa, Israel.
authors.forename: Ronen
authors.initials: R
authors.lastname: Spiegel
authors.affiliation: Monique and Jacques Roboh Department of Genetic Research, Hadassah, Hebrew University Medical Center, Jerusalem, Israel.
authors.forename: Ann
authors.initials: A
authors.lastname: Saada
authors.affiliation: Department of Immunology, Genetics and Pathology, Science for Life Laboratory Uppsala, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden.
authors.forename: Jonatan
authors.initials: J
authors.lastname: Halvardson
authors.affiliation: Monique and Jacques Roboh Department of Genetic Research, Hadassah, Hebrew University Medical Center, Jerusalem, Israel.
authors.forename: Devorah
authors.initials: D
authors.lastname: Soiferman
authors.affiliation: Monique and Jacques Roboh Department of Genetic Research, Hadassah, Hebrew University Medical Center, Jerusalem, Israel.
authors.forename: Avraham
authors.initials: A
authors.lastname: Shaag
authors.affiliation: Monique and Jacques Roboh Department of Genetic Research, Hadassah, Hebrew University Medical Center, Jerusalem, Israel.
authors.forename: Simon
authors.initials: S
authors.lastname: Edvardson
authors.affiliation: Department of Pediatric A', Emek Medical Center, Afula, Rappaport School of Medicine, Technion, Haifa, Israel.
authors.forename: Yoseph
authors.initials: Y
authors.lastname: Horovitz
authors.affiliation: Genetic Institute, Emek Medical Center, Afula, Rappaport School of Medicine, Technion, Haifa, Israel.
authors.forename: Morad
authors.initials: M
authors.lastname: Khayat
authors.affiliation: Genetic Institute, Emek Medical Center, Afula, Rappaport School of Medicine, Technion, Haifa, Israel.
authors.forename: Stavit A
authors.initials: SA
authors.lastname: Shalev
authors.affiliation: Department of Immunology, Genetics and Pathology, Science for Life Laboratory Uppsala, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Feuk
authors.affiliation: Monique and Jacques Roboh Department of Genetic Research, Hadassah, Hebrew University Medical Center, Jerusalem, Israel.
authors.forename: Orly
authors.initials: O
authors.lastname: Elpeleg
mesh_terms: D000293:Adolescent; D004252:DNA Mutational Analysis; D042967:Electron Transport Complex I / Q000235:genetics / Q000378:metabolism; D042963:Electron Transport Complex II / Q000235:genetics / Q000378:metabolism; D059472:Exome; D005260:Female; D005288:Ferredoxins / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D017240:Mitochondrial Myopathies / Q000235:genetics* / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000235:genetics* / Q000378:metabolism; D017354:Point Mutation
chemical_list: D005288:Ferredoxins; D024101:Mitochondrial Proteins; C478189:respiratory complex II; D042963:Electron Transport Complex II; D042967:Electron Transport Complex I