Description:

Dihydrolipoamide dehydrogenase (DLD), forms a subunit called the E3 component, is a component of the pyruvate dehydrogenase complex, the alpha-ketoglutarate dehydrogenase complex, and the branched-chain alpha-keto acid dehydrogenase complex (BCKD) and therefore is a vital component of important metabolic pathways. Dihydrolipoamide dehydrogenase is encoded by the DLD gene, which is located at 7q31-q32 of chromosome 7 and contains 14 exons. Up-to-date, twelve mutations in DLD gene have been reported in patients with dihydrolipoyl dehydrogenase deficiency [also known as E3-deficient maple syrup urine disease (MSUD3)], Ashkenazi Jewish families with lipoamide dehydrogenase (LAD) deficiency, Leigh syndrome, and atypical Form of α-Ketoglutarate Dehydrogenase Deficiency. Mutation types include missense mutations, splicing mutation, small deletion and small insertion. Most occurrences of E3 deficiency involve neurodegenerative symptoms, and the disease can be fatal. Individuals who present symptoms shortly after birth may not live beyond early childhood. One mutation to human E3 (G194C) is associated with an adult-onset form of E3 deficiency, this mutation is estimated to be carried by one in every 94 Ashkenazi Jews.

Reasons for Referral:

• Confirmation of a clinical diagnosis
• Carrier testing

Testing Methodology:

The exons and flanking intronic regions of the DLD gene are PCR amplified and sequenced in both the forward and reverse directions.

Specimen Requirements:

Blood: EDTA (purple-top) tubes: Adult: 14 cc; Child: 6 cc; Infant: 2-3 cc
Requisition form must accompany the specimen. To receive forms, additional information or specimen collection kits, please contact the laboratory.

Turnaround Time:

Index: 4 weeks
Known Familial Mutation: 2 weeks

CPT Codes and Prices:

Index: 83891, 83904x28, 83898x14, 83912, 83894x2
Known Familial Mutation: 83904x4, 83898x2, 83912, 83891, 83894x2

Shipping Information

Forms:

>> Gene Sequencing Requisition

Test Codes:

Index: 3460
Known Familial Mutation: 3461

Medical Genetics Laboratories
Baylor College of Medicine · Houston, TX 77030
Phone: 1-800-411-GENE · Fax: 713-798-6584
E-mail: