Evidence-Based Supplement & Herb Guides

RYR1 Genetic Test: Malignant Hyperthermia Risk and Anesthesia Results

Learn how RYR1 genetic testing evaluates malignant hyperthermia susceptibility, what positive, negative, and uncertain results mean, and how to plan safe trigger-free anesthesia.

An RYR1 genetic test looks for inherited variants associated with malignant hyperthermia susceptibility, a potentially fatal reaction to certain general anesthetics and the muscle...

SLC6A4 Genetic Test: Antidepressant Response, Serotonin Transporter, and Results

Understand SLC6A4 genetic testing, 5-HTTLPR and rs25531 results, the evidence on SSRI response, why guidelines do not recommend stand-alone prescribing changes, and how to use findings safely.

An SLC6A4 genetic test examines variants in the gene that encodes the serotonin transporter, the protein blocked by selective serotonin reuptake inhibitor antidepressants. The...

SLCO1B1 Genetic Test: Statin Muscle Risk, Simvastatin, and Results

Learn what an SLCO1B1 genetic test reveals about simvastatin exposure and statin muscle-risk, how results are reported, and how clinicians may use them safely.

An SLCO1B1 genetic test looks for inherited variants that can reduce the liver’s uptake of certain statins, especially simvastatin. When that transport is reduced,...

Statin Pharmacogenetic Test: SLCO1B1, Muscle Pain Risk, and Results

Understand how a statin pharmacogenetic test uses SLCO1B1, ABCG2, and CYP2C9 results to assess muscle-risk and guide safer, effective statin choices.

A statin pharmacogenetic test examines inherited variants that can change how the body transports or metabolizes cholesterol-lowering medicines. The most clinically established finding is...

Tacrolimus Pharmacogenetic Test: CYP3A5, Dose, Transplant, and Results

Learn how CYP3A5 pharmacogenetic testing can guide an initial tacrolimus dose after transplant, how results are interpreted, and why trough monitoring remains essential.

A tacrolimus pharmacogenetic test examines CYP3A5, a gene that strongly influences how quickly many transplant recipients clear tacrolimus. People who make functional CYP3A5 enzyme—called...

Thiopurine Pharmacogenetic Test: TPMT, NUDT15, Toxicity Risk, and Results

Learn how TPMT and NUDT15 pharmacogenetic testing predicts thiopurine toxicity risk, guides safer starting doses, and works with ongoing blood-count monitoring.

A thiopurine pharmacogenetic test examines TPMT and NUDT15, two genes that strongly influence tolerance to azathioprine, mercaptopurine, and thioguanine. Reduced function in either pathway...

TPMT Genetic Test: Thiopurine Toxicity, Azathioprine, Mercaptopurine, and Results

Learn how a TPMT genetic test predicts azathioprine and mercaptopurine toxicity risk, how metabolizer results guide starting doses, and why NUDT15 and blood monitoring still matter.

A TPMT genetic test identifies inherited variants that reduce thiopurine S-methyltransferase activity and increase sensitivity to azathioprine, mercaptopurine, and thioguanine. TPMT normally helps divert...

UGT1A1 Genetic Test: Irinotecan Toxicity, Gilbert Syndrome, and Results

Learn how UGT1A1 testing can predict irinotecan toxicity risk, support a Gilbert syndrome diagnosis, and clarify the meaning of *28, *6, and metabolizer results.

A UGT1A1 genetic test has two main clinical uses. In oncology, it can identify patients who clear the active irinotecan metabolite SN-38 more slowly...

VKORC1 Genetic Test: Warfarin Sensitivity, Dose, and Results

Learn how a VKORC1 genetic test predicts warfarin sensitivity, what G/G, G/A, and A/A results mean, and why dosing still requires CYP2C9 data and INR monitoring.

A VKORC1 genetic test examines inherited variation in the gene that makes warfarin’s molecular target. The result most often reported, VKORC1 c.-1639G>A (rs9923231), helps...

Warfarin Pharmacogenetic Test: CYP2C9, VKORC1, CYP4F2, Dose, and Results

Understand how a warfarin pharmacogenetic test uses CYP2C9, VKORC1, CYP4F2, and ancestry-aware results to estimate dose while INR monitoring guides safe treatment.

A warfarin pharmacogenetic test analyzes inherited variants that help explain why one person may need 1 mg of warfarin a day while another needs...

Alzheimer Disease Genetic Test: APOE, APP, PSEN1, PSEN2, and Results

Understand Alzheimer disease genetic testing for APOE, APP, PSEN1, and PSEN2, including who should test, result meanings, family risk, and treatment safety.

Alzheimer disease genetic testing can answer very different questions depending on which genes are examined. Rare pathogenic variants in APP, PSEN1, or PSEN2 can...

Amyotrophic Lateral Sclerosis (ALS) Genetic Test: C9orf72, SOD1, TARDBP, and Results

Learn how ALS genetic testing evaluates C9orf72, SOD1, TARDBP, FUS, and other genes, what results mean, and how findings can affect treatment and family risk.

ALS genetic testing looks for inherited or disease-associated changes that may explain why motor neurons are degenerating. The most important first-line targets include the...

Angelman Syndrome Genetic Test: UBE3A, Methylation, Deletion, and Results

Understand Angelman syndrome genetic testing for UBE3A, methylation, deletions, uniparental disomy, and imprinting defects, including results and recurrence risk.

Angelman syndrome testing does more than look for a change in the UBE3A gene. The condition results from loss of the active maternal UBE3A...

APOE Genotype Test: Alzheimer Disease Risk, Cholesterol, and Results

Learn what an APOE genotype test shows about Alzheimer disease risk, cholesterol disorders, anti-amyloid treatment safety, and ε2, ε3, and ε4 results.

An APOE genotype test identifies which common APOE alleles—ε2, ε3, or ε4—you inherited from each biological parent. The result can inform several separate clinical...

Autism Genetic Testing: Chromosomal Microarray, Exome Sequencing, and Results

Learn how chromosomal microarray, exome sequencing, genome sequencing, and targeted tests are used in autism, what results mean, and how findings may guide care.

Genetic testing does not diagnose autism; autism is diagnosed from development, communication, behavior, and clinical observation. Genetic testing looks for an underlying chromosome or...

Becker Muscular Dystrophy Genetic Test: DMD Gene, Muscle Weakness, and Results

Learn how Becker muscular dystrophy genetic testing detects DMD deletions, duplications, and sequence variants, and what results mean for weakness, heart care, and family risk.

Becker muscular dystrophy testing looks for a pathogenic change in the DMD gene, which provides instructions for making dystrophin. Becker muscular dystrophy usually occurs...

C9orf72 Genetic Test: ALS, Frontotemporal Dementia, and Results

Understand how C9orf72 repeat expansion testing relates to ALS and frontotemporal dementia, how results are classified, and what they mean for family risk.

A C9orf72 genetic test looks for an abnormal expansion of the six-letter DNA sequence GGGGCC in the C9orf72 gene. This expansion is an important...

Charcot-Marie-Tooth Disease Genetic Test: PMP22, GJB1, MFN2, MPZ, and Results

Learn how Charcot-Marie-Tooth genetic testing evaluates PMP22, GJB1, MFN2, MPZ, copy-number changes, inheritance, and positive, negative, or uncertain results.

Charcot-Marie-Tooth disease genetic testing searches for an inherited cause of a slowly progressive peripheral neuropathy. The most frequent findings involve PMP22, GJB1, MFN2, or...

Congenital Myasthenic Syndrome Genetic Test: Neuromuscular Junction Genes and Results

Understand congenital myasthenic syndrome genetic panels, neuromuscular junction genes, result categories, inheritance, and why the exact subtype can change treatment.

Congenital myasthenic syndrome genetic testing looks for inherited variants that disrupt communication between a motor nerve and muscle at the neuromuscular junction. These disorders...

CYP2D6 and CYP2C19 Psychiatric Medication Pharmacogenetic Test: Antidepressant Results

Understand CYP2D6 and CYP2C19 antidepressant pharmacogenetic results, metabolizer phenotypes, drug interactions, dosing implications, and test limitations.

A CYP2D6 and CYP2C19 psychiatric medication pharmacogenetic test examines inherited differences in two liver-enzyme genes that help process many antidepressants. The result may explain...