COMPLEX IV (COX) DEFICIENCY

COX6B1 is a hydrophilic extramembrane protein that interacts with cytrochrome c and participates in the dimerization of Cytochrome c oxidase (COX, complex IV). Human COX6B1 gene maps to 19q13.12 and contains 4 exons. Exon 1 is a non-coding; exons 2-4 encode 86 amino acids. A homozygous 221G>A (p.R19H) mutation has been reported in the COX6B1 gene in 2 Saudi Arabian siblings (OMIM 124089.0001). These individuals developed muscle weakness and pain, seizures, unsteady or ataxic gait, visual disturbances, rapidly progressive neurologic deterioration, leukodystrophic brain changes, increased serum and CSF lactate, and decreased COX activity in muscle.

Reasons for Referral:

• Confirmation of a clinical diagnosis
• Carrier testing

Testing Methodology:

The exons and flanking intronic regions of the COX6B1 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: 83912, 83894, 83891, 83898x4, 83904x8, 83909x8
Known Familial Mutation: 83912, 83894, 83891, 83898, 83904x2, 83909x2

Shipping Information

Forms:

>> Mitochondrial Requisition - Mitochondrial Diagnostic Checklist is included

References:

1. Quinzii C, Naini A, Salviati L, et al. A Mutation in Para-Hydroxybenzoate-Polyprenyl Transferase (COQ2) Causes Primary Coenzyme Q10 Deficiency. Am. J. Hum. Genet. 2006; 78:345–349.

Test Codes:

Index: 3625
Known Familial Mutation: 3626

Medical Genetics Laboratories
Baylor College of Medicine · Houston, TX 77030
Phone: 1-800-411-GENE · Fax: 713-798-2787
E-mail: