Overview: Non-Alcoholic Fatty Liver Disease PNPLA3 TM6SF2 Genotyping Panel
Introduction: The Non-Alcoholic Fatty Liver Disease PNPLA3 TM6SF2 Genotyping Panel is a diagnostic tool designed to screen for genetic predisposition to NAFLD using whole blood samples. In India, NAFLD affects ~20-30 percent of urban adults and ~10-15 percent in rural areas (rising rapidly due to obesity, diabetes, metabolic syndrome), with PNPLA3 rs738409 (I148M) and TM6SF2 rs58542926 variants strongly associated with increased hepatic fat accumulation, fibrosis progression, and HCC risk (PNPLA3 GG genotype ~2-3-fold higher severity). High morbidity from under-testing in rural/low-SES patients with fatty liver on ultrasound or elevated ALT, limited genetic labs, delayed lifestyle intervention or pioglitazone/vitamin E leading to advanced fibrosis/cirrhosis. Per hepatology practices aligned with ICMR and INASL guidelines, the test employs PCR for PNPLA3 and TM6SF2 genotypes over 1-2 days with high accuracy, valuable for risk stratification in NAFLD patients. This diagnostic falls under genetic screening and targets patients with NAFLD (especially young, lean, or familial), addressing accurate detection to guide intensive monitoring or early therapy. With elevated morbidity due to underdiagnosis, the test supports public health efforts by enabling precise genetic risk assessment and reducing NAFLD progression burden. Its whole blood-based approach ensures reliable SNP genotyping.
Other Names: NAFLD Geno Pnl.
FDA Status: FDA approved, CLIA certified for molecular pathology, compliant with 2025 standards.
Historical Milestone: PNPLA3/TM6SF2 variants identified 2008-2014; in India, emerging in NAFLD research.
Purpose: The test assesses 2 parameters including PNPLA3 genotype to guide NAFLD genetic predisposition screening, assess fibrosis/HCC risk, inform management.
Test Parameters: 1. PNPLA3 Genotype, 2. TM6SF2 Genotype.
Pretest Condition: No fasting required; patients should have NAFLD on imaging or elevated ALT.
Specimen: 3 mL whole blood in 1 EDTA tube, transported within specified times to maintain sample viability.
Sample Stability at Room Temperature: 48 hours with proper handling to preserve DNA integrity, ensuring reliable test performance.
Sample Stability at Refrigeration: 7 days at 2-8 degrees Celsius, suitable for short-term storage before laboratory processing, though immediate testing is preferred.
Sample Stability at Frozen: Not applicable (fresh sample preferred for PCR).
Medical History: Patients should provide details on BMI, diabetes, family NAFLD.
Consent: Written informed consent is required, detailing the test's purpose, potential risks of high-risk genotype including progression, benefits of screening, and minimal discomfort from blood draw.
Procedural Considerations: The test involves sample processing using PCR by trained personnel to ensure sterile technique, avoid contamination, and interpret genotypes within 1-2 days using provided controls. Laboratories must maintain a controlled environment, adhere to quality assurance protocols.
Factors Affecting Result Accuracy: Delays beyond stability periods, improper storage conditions, or low DNA yield can affect results. Correlation with clinical evaluation or additional testing is recommended to confirm findings.
Clinical Significance: PNPLA3 GG or TM6SF2 variant indicates higher NAFLD severity, necessitating specialist input.
Specialist Consultation: Hepatologists should be consulted for management.
Additional Supporting Tests: FibroScan, liver enzymes for confirmation.
Test Limitations: Genetic risk only; comprehensive approach required.
References: Indian Journal of Gastroenterology 2024, NAFLD Studies India 2023.
