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Pyruvate Dehydrogenase Phosphatase Deficiency: Identification of the First Mutation in Two Brothers and Restoration of Activity by Protein Complementation


Maj, Mary C; MacKay, Neviana; Levandovskiy, Valeriy; Addis, Jane; Baumgartner, E Regula; Baumgartner, Matthias R; Robinson, Brian H; Cameron, Jessie M (2005). Pyruvate Dehydrogenase Phosphatase Deficiency: Identification of the First Mutation in Two Brothers and Restoration of Activity by Protein Complementation. Journal of Clinical Endocrinology & Metabolism, 90(7):4101-4107.

Abstract

Context: Pyruvate dehydrogenase phosphatase (PDP) deficiency has been previously reported as an enzymopathy, but the genetic basis for such a defect has never been established.

Objective: The aim of this study was to identify the cause of the defect in two patients who presented with PDP deficiency.

Patients: We studied two brothers of consanguineous parents who presented with neonatal hypotonia, elevated lactate, and less than 25% native pyruvate dehydrogenase complex (PDHc) activity in skin fibroblasts compared with controls. The activity of the complex could be restored to normal values by preincubation of the cells with dichloroacetate or by treating cell extracts with calcium.

Results: These two individuals were found to be homozygous for a 3-bp deletion in the coding sequence of the PDP isoform 1 (PDP1), which removes the amino acid residue leucine from position 213 of the protein. A recombinant version of this protein was synthesized and found to have a very reduced (<5%) ability to activate purified PDHc. Reduced steady-state levels of PDP1 in the patient’s fibroblasts coupled with the low catalytic activity of the mutant PDP1 resulted in native PDHc activity being reduced, but this could be corrected by the addition of recombinant PDP1 (wild type).

Conclusion: We have identified mutations in PDP1 in two brothers with PDP deficiency and have proven that the mutation is disease-causing. This is the first demonstration of human disease due to a mutation in PDP1.

Abstract

Context: Pyruvate dehydrogenase phosphatase (PDP) deficiency has been previously reported as an enzymopathy, but the genetic basis for such a defect has never been established.

Objective: The aim of this study was to identify the cause of the defect in two patients who presented with PDP deficiency.

Patients: We studied two brothers of consanguineous parents who presented with neonatal hypotonia, elevated lactate, and less than 25% native pyruvate dehydrogenase complex (PDHc) activity in skin fibroblasts compared with controls. The activity of the complex could be restored to normal values by preincubation of the cells with dichloroacetate or by treating cell extracts with calcium.

Results: These two individuals were found to be homozygous for a 3-bp deletion in the coding sequence of the PDP isoform 1 (PDP1), which removes the amino acid residue leucine from position 213 of the protein. A recombinant version of this protein was synthesized and found to have a very reduced (<5%) ability to activate purified PDHc. Reduced steady-state levels of PDP1 in the patient’s fibroblasts coupled with the low catalytic activity of the mutant PDP1 resulted in native PDHc activity being reduced, but this could be corrected by the addition of recombinant PDP1 (wild type).

Conclusion: We have identified mutations in PDP1 in two brothers with PDP deficiency and have proven that the mutation is disease-causing. This is the first demonstration of human disease due to a mutation in PDP1.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > University Children's Hospital Zurich > Medical Clinic
Dewey Decimal Classification:610 Medicine & health
Scopus Subject Areas:Health Sciences > Endocrinology, Diabetes and Metabolism
Life Sciences > Biochemistry
Life Sciences > Endocrinology
Life Sciences > Clinical Biochemistry
Health Sciences > Biochemistry (medical)
Language:English
Date:2005
Deposited On:04 Feb 2020 14:24
Last Modified:31 Jul 2020 03:45
Publisher:Oxford University Press
ISSN:0021-972X
OA Status:Closed
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.1210/jc.2005-0123
PubMed ID:15855260

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