- Patient Preparation
- Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
- Specimen Preparation
- Transport 3 mL whole blood. (Min: 2 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Characteristics: Hereditary paraganglioma-pheochromocytoma (PGL/PCC) syndromes are characterized by paragangliomas (neuroendocrine tumors of the autonomic nervous system) and pheochromocytomas (paragangliomas of the adrenal medulla). Pathogenic germline mutations in a number of genes, including SDHB, predispose to paraganglioma and pheochromocytoma with risk of malignant transformation.
Incidence: About 1 in 300,000 per year.
Inheritance: Autosomal dominant.
Cause: Pathogenic succinate dehydrogenase, subunits B, C, and D (SDHB, SDHC, and SDHD) gene mutations. Mutations in other genes, including TMEM127, EGLN1, MAX, SDHA, and SDHAF2, may also be causative.
Clinical Sensitivity: 7-11 percent.
Methodology: Bidirectional sequencing of all coding regions and intron-exon boundaries of the SDHB gene; Multiplex Ligation-dependent Probe Amplification (MLPA) to detect large SDHB deletions/duplications.
Analytical Sensitivity and Specificity: Sequencing: 99 percent. MLPA: 90 and 99 percent, respectively.
Limitations:Diagnostic errors can occur due to rare sequence variations. Regulatory region mutations and deep intronic mutations will not be detected. The breakpoints of large deletions/duplications will not be determined. Mutations in genes other than SDHB are not evaluated.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
|Component Test Code*||Component Chart Name||LOINC|
|2007109||HPGL-PCC (SDHB) Seq, DelDup Specimen||31208-2|
|2007110||HPGL-PCC (SDHB) Seq, DelDup Interp||41062-1|
- Paraganglioma (SDHB) Sequencing and Deletion/Duplication
- PCC (SDHB) Sequencing and Deletion/Duplication
- PGL (SDHB) Sequencing and Deletion/Duplication
- Pheochromocytoma (SDHB) Sequencing and Deletion/Duplication
- SDHB Sequencing and Deletion/Duplication
- Stromal Tumor (SDHB) Sequencing and Deletion/Duplication
- Succinate Dehydrogenase, subset B (SDHB) Sequencing and Deletion/Duplication