Overview: NGS Exome Sequencing TestIntroduction: The NGS Exome Sequencing Test sequences the exome to diagnose genetic disorders, causing developmental or neurological issues. Following 2023 ACMG guidelines, it uses PCR 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 genetic disorders.
Other Names: Clinical Exome Assay, Whole Exome Sequencing Test.
FDA Status: Laboratory-developed test (LDT), meeting molecular pathology standards for diagnostic accuracy.
Historical Milestone: Exome sequencing began in the 2000s with genomic research. Next-generation sequencing (NGS) methods improved in the 2010s, enhancing diagnostic precision.
Purpose: Sequences exome to diagnose genetic disorders, guides treatment, and evaluates patients with developmental or neurological issues.
Test Parameters: 1. Exome Sequence
Pretest Condition: No fasting required. Collect whole blood, buccal swab, or saliva. Report history of developmental delays, neurological issues, or genetic symptoms.
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 developmental delays, neurological issues, or family history of genetic disorders. Include current medications, especially anticonvulsants.
Consent: Written consent required, detailing the tests purpose, genetic disorder implications, and risks of sample collection.
Procedural Considerations: Uses next-generation sequencing (NGS) to analyze the exome in specimens. Results are available in 3-5 days, supporting clinical decisions. Performed in laboratories, often for genetic disorder diagnosis.
Factors Affecting Result Accuracy: Low DNA yield or improper sample storage can affect results. Contamination may reduce specificity.
Clinical Significance: Identified mutations confirm genetic disorders, guiding targeted therapy or genetic counseling. Negative results may require whole-genome sequencing.
Specialist Consultation: Consult a geneticist for result interpretation and treatment planning.
Additional Supporting Tests: Karyotyping, microarray, or specific gene panels to confirm genetic disorder diagnosis.
Test Limitations: Not all genetic disorders are exome-based; clinical correlation is needed. Sample quality affects sensitivity.
References: ACMG Genetic Testing Guidelines, 2023; American Journal of Human Genetics, Bamshad MJ, 2022.
