Dihydrolipoamide Dehydrogenase DLD Gene Analysis

Dihydrolipoamide dehydrogenase (DLD) is a component (E3) that is common to the pyruvate dehydrogenase complex, the alpha-ketoglutarate dehydrogenase complex, and the branched-chain alpha-keto acid dehydrogenase complex. Mutations in this gene have been identified in patients with variable multiple metabolic abnormalities related to deficiencies of these three enzymes, associated with ataxia, Leigh syndrome, other neurological manifestations, and sometime hepatic dysfunction. This rare disorder has been called maple syrup urine disease type III, but is quite different from MSUD.

DLD Known Familial Mutation Analysis is available for family members when a mutation has been identified. DLD Prenatal Diagnosis is also available for families who have had a mutation identified or by special arrangement in advance with the director.

DLD gene sequencing is available as part of a panel of PDC deficiency genes sequenced. The PDC Deficiency panel also includes PDHA gene sequencing, PDHB gene sequencing, DLAT gene sequencing and PDHX gene sequencing.

Indications for Testing

  • Confirmation of basis of metabolic and clinical features described above or enzymatic deficiency of E3
  • Confirmation of a clinical/biochemical diagnosis of dihydrolipoamide dehydrogenase deficiency
  • Targeted mutation analysis for known familial mutations
  • Pregnancy known to be at risk for pyruvate dehydrogenase deficiency and a known DLD familial mutation.

OMIM #: 238331

Sample Requirements

  • Infants: 2-3 mL whole blood in purple top EDTA tube
  • Children (>2 years) and adults: 3-4 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 tube along with prenatal sample.

Cultured fibroblasts and tissue remaining from fresh liver/muscle biopsy performed for enzyme analysis may also be used for DNA analysis. Cell Line Build Up is available, as is DNA Extract and Store. Enzyme analysis of E3, PDC, and KDC 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

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

Turnaround Time

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

CPT Code

DLD Gene Sequencing: 81406
DLD Prenatal Analysis: 81404
DLD Known Familial Mutation Analysis: 81403

Please submit a completed Molecular Requisition for each sample.