title: Difficulties in recognition of pyruvate dehydrogenase complex deficiency on the basis of clinical and biochemical features. The role of next-generation sequencing.
abstract: Pyruvate dehydrogenase complex (PDHc) defect is a well-known cause of mitochondrial disorders (MD) with at least six responsible genes (PDHA1, PDHB, DLAT, DLD, PDHX, PDP1). The aim of this work was to assess the diagnostic value of biochemical methods in recognition of PDHc defect in Polish patients with suspicion of MD. In the first step, Western blot of the E1α subunit was performed on 86 archive muscle bioptates with suspicion of MD. In the second step, Sanger PDHA1 sequencing was performed in 21 cases with low E1α expression. In the third step, 7 patients with negative results of PDHA1 sequencing were subjected to whole-exome sequencing (WES). This protocol revealed 4 patients with PDHA1 and one with DLD mutations. Four additional probands were diagnosed outside the protocol (WES or Sanger sequencing). The molecular characterization of PDHc defect was conducted in a total of 9 probands: 5 according to and 4 off the protocol. Additionally, two affected relatives were recognized by a family study. Altogether we identified seven different PDHA1 changes, including two novel variants [c.464T > C (p.Met155Thr) and c.856_859dupACTT (p.Arg288Leufs*10)] and one DLD variant. The lactate response to glucose load in the PDHA1 subset was compared to a subset of non PDHc-related MD. Opposite responses were observed, with an increase of 23% and decrease of 27%, respectively. The results show that determining lactate response to glucose load and muscle E1α expression may contribute to distinguishing PDHc-related and other MD, however, WES is becoming the method of choice for MD diagnostics.
authors.affiliation: Department of Medical Genetics, The Children's Memorial Health Institute, Warsaw, Poland.
authors.forename: E
authors.initials: E
authors.lastname: Ciara
authors.affiliation: Department of Pediatrics, Nutrition and Metabolic Diseases, The Children's Memorial Health Institute, Warsaw, Poland.
authors.forename: D
authors.initials: D
authors.lastname: Rokicki
authors.affiliation: Department of Medical Genetics, The Children's Memorial Health Institute, Warsaw, Poland.
authors.forename: P
authors.initials: P
authors.lastname: Halat
authors.affiliation: Department of Pathology, The Children's Memorial Health Institute, Warsaw, Poland.
authors.forename: A
authors.initials: A
authors.lastname: Karkucińska-Więckowska
authors.affiliation: Department of Medical Genetics, The Children's Memorial Health Institute, Warsaw, Poland.
authors.forename: D
authors.initials: D
authors.lastname: Piekutowska-Abramczuk
authors.affiliation: Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria.
authors.forename: J
authors.initials: J
authors.lastname: Mayr
authors.affiliation: Department of Medical Genetics, The Children's Memorial Health Institute, Warsaw, Poland.
authors.forename: J
authors.initials: J
authors.lastname: Trubicka
authors.affiliation: Department of Pathology, The Children's Memorial Health Institute, Warsaw, Poland.
authors.forename: T
authors.initials: T
authors.lastname: Szymańska-Dębińska
authors.affiliation: Department of Pathology, The Children's Memorial Health Institute, Warsaw, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Pronicki
authors.affiliation: Department of Biochemistry and Experimental Medicine, The Children's Memorial Health Institute, Warsaw, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Pajdowska
authors.affiliation: Department of Child Neurology, Chorzowskie Centrum Pediatrii i Onkologii, Chorzów, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Dudzińska
authors.affiliation: Department of Pediatrics, Endocrinology, Diabetology, Metabolic Diseases and Cardiology, Pomeranian Medical University, Szczecin, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Giżewska
authors.affiliation: Department of Medical Genetics, The Children's Memorial Health Institute, Warsaw, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Krajewska-Walasek
authors.affiliation: Department of Pediatrics, Nutrition and Metabolic Diseases, The Children's Memorial Health Institute, Warsaw, Poland.
authors.forename: J
authors.initials: J
authors.lastname: Książyk
authors.affiliation: Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria.
authors.forename: W
authors.initials: W
authors.lastname: Sperl
authors.affiliation: Department of Medical Genetics, Warsaw Medical University, Warsaw, Poland.
authors.forename: R
authors.initials: R
authors.lastname: Płoski
authors.affiliation: Department of Medical Genetics, The Children's Memorial Health Institute, Warsaw, Poland; Department of Pediatrics, Nutrition and Metabolic Diseases, The Children's Memorial Health Institute, Warsaw, Poland.
authors.forename: E
authors.initials: E
authors.lastname: Pronicka
keywords: DLD; Novel pathogenic variants; PDHA1; PDHc; Pyruvate dehydrogenase complex deficiency; Whole-exome sequencing