Overview: CPS1 Mutation TestIntroduction: The CPS1 Mutation Test tests for CPS1 gene mutations to diagnose carbamoyl phosphate synthetase I deficiency, a rare disorder causing ammonia buildup, seizures, or developmental delays. Affecting 1 in 100,000 newborns, this disorder poses diagnostic challenges due to its rarity. Following 2023 National Organization for Rare Disorders (NORD) guidelines, it uses PCR/sequencing for high accuracy, supporting molecular pathology screening. This test is essential for diagnosis, genetic counseling, and improving outcomes in pediatrics.
Other Names: CPS1 Deficiency Test, CPS1 Gene Assay.
FDA Status: Laboratory-developed test (LDT), meeting pathology standards for diagnostic reliability.
Historical Milestone: Genetic testing for metabolic disorders began in the 1990s with research by Summar, who identified CPS1 mutations. PCR/sequencing advancements in the 2000s by Illumina improved detection, surpassing earlier Southern blot methods.
Purpose: Detects CPS1 mutations to diagnose deficiency, guides dietary therapy or ammonia scavengers, and evaluates patients with seizures, aiming to prevent coma.
Test Parameters: CPS1 gene mutations
Pretest Condition: No special preparation required. Collect whole blood, buccal swab, or saliva. Report history of neurological issues.
Specimen: Whole Blood (EDTA, 3-5 mL), Buccal Swab (sterile swab, 1-2 swabs), Saliva (sterile container, 1-2 mL); 4 mL whole blood in EDTA tube. Transport in a biohazard container.
Sample Stability at Room Temperature: 24 hours
Sample Stability at Refrigeration: 1 week
Sample Stability at Frozen: 1 month
Medical History: Document seizures or developmental delay. Include current medications or family history of metabolic disorders.
Consent: Written consent required, detailing the test's purpose, disease risks (e.g., coma), and sample collection risks.
Procedural Considerations: Uses PCR/sequencing to detect mutations, requiring labs with thermal cyclers. Results available in 5-7 days. Performed in labs with strict handling.
Factors Affecting Result Accuracy: Sample degradation or contamination can affect results. Medications may not affect results but require correlation.
Clinical Significance: Positive mutations confirm deficiency, guiding therapy. Early treatment might prevent coma, while untreated cases lead to death. Normal results may require ammonia tests.
Specialist Consultation: Consult a pediatrician or genetic counselor for interpretation.
Additional Supporting Tests: Ammonia level, urine organic acids, or genetic panel to confirm diagnosis.
Test Limitations: Specific to CPS1; correlation with symptoms needed. False negatives possible with untested variants.
References: NORD Guidelines, 2023; Journal of Inherited Metabolic Disease, Summar ML, 2022.
