Genetic and metabolic medicine
Single gene testing and interpreting common genetic test results
When a single gene test beats a panel, which method fits which variant type, how to read a report line by line, and how to explain reduced penetrance, attenuated phenotypes, variants of uncertain significance and CFTR results to patients.
Tier 2Medical sciences concept
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- A single gene test suits a phenotype that points to one gene, a variant type that panels miss (repeat expansions, large deletions), or a known familial variant.
- Most new diagnostic testing now uses panels or exomes (see massively parallel sequencing). Single-variant testing dominates cascade and predictive testing.
- Every result answers three separate questions. Is the variant disease-causing (classification)? How likely is disease (penetrance)? How severe will it be (expressivity)?
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Sources
- Richards S, Aziz N, Bale S et al. Standards and guidelines for the interpretation of sequence variants: a joint consensus recommendation of the ACMG and AMP. Genet Med 2015;17:405-424American College of Medical Genetics and Genomics, 2015 (with ClinGen SVI refinements)
- den Dunnen JT, Dalgleish R, Maglott DR et al. HGVS recommendations for the description of sequence variants: 2016 update. Hum Mutat 2016;37:564-569Human Genome Variation Society, 2016 (current recommendations maintained online)
- Farrell PM, White TB, Ren CL et al. Diagnosis of cystic fibrosis: consensus guidelines from the Cystic Fibrosis Foundation. J Pediatr 2017;181S:S4-S15Cystic Fibrosis Foundation, 2017
- Nykamp K, Truty R, Riethmaier D et al. Elucidating clinical phenotypic variability associated with the polyT tract and TG repeats in CFTR. Hum Mutat 2021;42:1165-1172Human Mutation, 2021
- CFTR2 variant databaseJohns Hopkins University and Cystic Fibrosis Foundation
- MBS item 73317: detection of the C282Y mutation of the HFE geneAU/NZAustralian Government Department of Health, Disability and Ageing (MBS Online), 2026
- MBS item 73451: reproductive carrier testing for CFTR, SMN1 and FMR1AU/NZAustralian Government Department of Health, Disability and Ageing (MBS Online), 2026
- Genetic testing resources for cliniciansAU/NZHuman Genetics Society of Australasia
- Last updated
- 14 November 2026
What changed
- 14 November 2026 Turnstile bot check on sign-in and signed-out feedback