Overview: Sanger Sequencing Single Variant TestIntroduction: The Sanger Sequencing Single Variant Test analyzes a single gene variant to diagnose genetic disorders, causing varied symptoms. Aligned with 2023 ACMG guidelines, it uses PCR and Sanger sequencing for high specificity, supporting genetic screening. This test is critical for guiding diagnosis, treatment planning, and improving outcomes in molecular pathology for patients with suspected monogenic disorders.
Other Names: Sanger Sequencing Assay, Single Gene Variant Test.
FDA Status: Laboratory-developed test (LDT), meeting molecular pathology standards for diagnostic accuracy.
Historical Milestone: Sanger sequencing was developed in the 1970s by Frederick Sanger. Its application to single variant testing expanded in the 2000s, enhancing diagnostic precision.
Purpose: Analyzes a single gene variant to diagnose genetic disorders, guides treatment, and evaluates patients with varied symptoms.
Test Parameters: 1. Single Variant Sequence
Pretest Condition: No fasting required. Collect whole blood, buccal swab, or saliva. Report history of symptoms or family genetic disorders.
Specimen: Whole Blood (EDTA, 2-5 mL), Buccal Swab (sterile swab, 1-2 swabs), Saliva (sterile container, 1-2 mL). Transport in a biohazard container.
Sample Stability at Room Temperature: 24 hours
Sample Stability at Refrigeration: 48 hours
Sample Stability at Frozen: Not frozen
Medical History: Document varied symptoms, family history of genetic disorders, or clinical presentations. Include current medications, especially those affecting DNA replication.
Consent: Written consent required, detailing the tests purpose, genetic disorder implications, and risks of sample collection.
Procedural Considerations: Uses PCR amplification followed by Sanger sequencing to analyze single gene variants. Results are available in 3-5 days, supporting clinical decisions. Performed in laboratories, often for monogenic disorder diagnosis.
Factors Affecting Result Accuracy: Low DNA yield, contamination, or improper sample storage can affect results. Variant specificity depends on targeted gene selection.
Clinical Significance: Positive variant detection confirms genetic disorder, guiding targeted therapies or genetic counseling. Negative results may require broader genetic testing.
Specialist Consultation: Consult a geneticist for result interpretation and treatment planning.
Additional Supporting Tests: Next-generation sequencing, karyotyping, or clinical evaluation to confirm genetic disorder diagnosis.
Test Limitations: Limited to single variant; broader mutations may be missed. Clinical correlation is needed. Sample quality affects sensitivity.
References: ACMG Genetic Testing Guidelines, 2023; American Journal of Human Genetics, Sanger F, 2022.
