Glossary
Every term in plain words.
A short list of the terms you will meet in your Longevity Essential Analysis, each in one clear sentence. Read it before you begin, while you go through your results, or whenever a word stops you and you want a quick reminder.
Variant
A spot where your DNA differs from most people's.
Almost all of your three billion DNA letters match a standard human reference. Where yours differs, a changed letter, a small insertion, a missing piece, that difference is a variant. Your analysis is, in essence, a careful walk through the variants that matter for you.
Allele
Your version of a variant on one of your two gene copies.
You inherit two copies of each gene, one from each parent. The version you carry on a given copy is an allele. Having the variant on one copy is heterozygous; on both copies is homozygous. The difference matters, because some conditions need the variant on both copies to show up, others need only one.
Heterozygous · Homozygous
Having a variant on one gene copy, or on both.
One variant copy and one ordinary copy is heterozygous (often shortened to 'het'). Two variant copies is homozygous. For recessive conditions, most of the inheritance area, having one copy usually means you carry it without symptoms; having both copies means you are affected.
Penetrance
How often a variant actually leads to the condition.
Carrying a variant linked to a condition does not mean the condition will appear. Penetrance is the chance that it does, sometimes near 100%, sometimes 30%, sometimes less. Your analysis reports findings with this in mind: a low-penetrance variant is a tendency, not a verdict.
ACMG classification
The five-step scale clinical labs use to rate how serious a variant is.
Clinical labs grade a variant as Pathogenic, Likely Pathogenic, Uncertain Significance (VUS), Likely Benign, or Benign, following standards set by the American College of Medical Genetics and the Association for Molecular Pathology. Your Helixir Genomics analysis reads these ratings where they already exist in ClinVar, but does not issue its own. Formal ACMG-graded reports come from clinical labs and from the whole-genome reading offered by Helixir Health.
ClinVar
The NIH's free public record of what each variant is known to mean.
ClinVar gathers what has been published about specific variants: which condition each has been linked to, how strong the evidence is, and who reported it. It is the first place we check when reading what a variant might mean for your health; the original research papers are the second.
Polygenic risk score
One number that adds up the tiny effects of thousands of variants on a single trait.
Most common traits, your height, LDL cholesterol, type-2 diabetes, blood pressure, are shaped by thousands of variants, each nudging the result a little. A polygenic score totals those small nudges into one figure. We treat that figure as a general direction, never a personal prediction: it captures only part of what is inherited, and it is tuned to specific population ancestries.
Genotype
Your DNA read at about a million chosen spots, not the whole thing.
A consumer DNA file (23andMe, AncestryDNA) reads about a million well-studied spots across your genome. It samples your DNA rather than reading all of it. Most of what your Helixir Genomics analysis covers can be answered from a genotype. The areas that need rare variants or deeper reading, the kind Helixir Health offers, cannot.
Whole-genome sequencing (WGS)
Reading all three billion DNA letters, the depth used for clinical work.
WGS reads every position, not only the well-studied ones. It can find rare variants, large rearranged sections, and the detailed drug-response signals a genotype file cannot. It is the foundation of the Helixir Health analysis, and is not used at the Helixir Genomics tier.
Pharmacogenomics
How your DNA changes the way your body handles medicines.
Your genes shape the enzymes and proteins that break down and move drugs through your body, which is why a standard dose can be right for one person and too strong or too weak for another. This is a common area in our analyses, and the one most often worth sharing with your physician.
Carrier
Someone who carries one copy of a recessive variant but has no symptoms.
A carrier has one copy of a recessive variant and one ordinary copy, so the condition itself does not show up in them. This matters most when planning a child: if both parents carry the same one, each pregnancy has a one-in-four chance of a child who is affected.
Haplogroup
A branch on the human family tree, followed down one ancestral line.
Your maternal haplogroup passes from your mother, to her mother, and back through the generations. If your DNA carries a Y haplogroup, it traces the matching father-to-father line. Together they map two of your deepest ancestries back into prehistory.
Imputation
Filling in nearby variants your file did not directly measure.
When an area of your analysis needs a variant your DNA file did not test directly, we estimate it from large reference datasets of people whose DNA is fully read. In most regions this is highly reliable, and we are never quiet about it: any estimated variant is clearly labelled as such in your analysis.
Reference allele
The 'standard' version of a variant your DNA is compared against.
Your DNA is read against a shared human reference genome (currently the version called GRCh38), and the reference allele is what it carries at a given spot. A 'risk allele' is the version linked to a trait or condition. Carrying it does not mean you have the trait, only that you carry the variant.
If a term in your Longevity Essential Analysis is not here, write to us, we will add it.
Words to the work
Now see what they say about your longevity.
Definitions are only useful next to your own results. Yours are read by a scientist, then turned into a small number of choices that compound over a lifetime.