PDHB Gene Analysis

Pyruvate dehydrogenase, the first component (E1) of the pyruvate dehydrogenase complex (PDC), is a homotetramer consisting of 2 alpha subunits (encoded by PDHA1 on chromosome X) and 2 beta subunits (encoded by PDHB on chromosome 3). The enzyme, which is found in mitochondria, catalyzes thiamine pyrophosphate dependent decarboxylation of pyruvate, and together with other catalytic components of PDC converts pyruvate, coenzyme A, and NAD to acetyl-CoA, CO2, and NADH. Patients with PDHB mutations present with lactic acidemia and neurological dysfunction (similar to those with PDHA1 mutations) and reduced PDC activity in cultured skin fibroblasts, lymphocytes, or muscle.

For patients with deficient PDC enzyme activity or strongly clinically suspected PDC deficiency, PDHA1 gene sequence analysis is recommended as the first step in mutation identification. PDHB gene sequence analysis is available as a follow-up test or can be ordered as the initial test when clinically indicated. PDHB known familial mutation analysis is available for family members when a mutation has been identified through analysis performed in this laboratory. PDHB prenatal diagnosis is also available for families who have had a mutation identified through analysis performed in this laboratory or by special arrangement in advance with the director.

Test Indications

  • Confirmation of a clinical/biochemical diagnosis of pyruvate dehydrogenase deficiency
  • Targeted mutation analysis for known familial mutations.
  • Pregnancy known to be at risk for pyruvate dehydrogenase deficiency and a known PDHB familial mutation.

OMIM#: 179060

Sample requirements

  • Infants: two to three mL whole blood in purple top EDTA tube
  • Children (>2 years) and adults: five to seven mL whole blood in purple top EDTA tube
  • Amniotic fluid or cultured amniocytes
  • Chorionic villi or cultured chorionic villi

Contact laboratory genetic counselors or molecular director for specific sample requirements in advance.

Note: Maternal blood sample is also required for maternal cell contamination studies for prenatal samples. Send five mL purple top EDTA along with prenatal sample.

Cultured skin fibroblasts, blood lymphocytes, and frozen tissue from fresh muscle or liver biopsies performed for enzyme analysis may also be used for DNA analysis. Cell line build up is available, as is DNA extraction and storage. Enzyme assay for PDH may be arranged directly with the Center for Inherited Disorders of Metabolism (CIDEM).

Sample Handling

Blood samples stored overnight should be refrigerated or kept cold. Blood samples should never be frozen. Specimens being sent from outside facilities should be packaged with a cold pack according to standard medical safety practices. The specimen should be shipped by overnight priority (scheduled to arrive by Friday morning at the latest).

Shipping Address

Center for Human Genetics Laboratory
10524 Euclid Ave, Sixth Floor
Cleveland, OH 44106
216-983-1134

For local samples, please call Client Service (216-844-5227) to arrange for sample pick-up.

Turnaround Time

PDHB Sequencing – 3 weeks
PDHB Known Familial Mutation analysis – 1 week
PDHB Prenatal Diagnosis – 1 week

CPT Codes

PDHB Gene Sequencing: 81405
PDHB Prenatal Analysis: 81404
PDHB Known Familial Mutation Analysis: 81403

Please submit a completed Prenatal and Postnatal Cytogenetics and Molecular specimens requisition for each sample.

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