An enlarged thyroid with one or more lumps, almost always non-cancerous -- and, per the largest thyroid genetics study yet, genetically correlated with the disease it is most often confused with the risk of: thyroid cancer.
Benign nodular goiter is an enlarged thyroid gland containing one or more distinct lumps (nodules) that are not cancerous. It is extremely common — thyroid nodules turn up in a large share of adults once anyone looks with ultrasound, most causing no symptoms at all, and the great majority never become cancer. The clinical question a nodule actually raises is not "is this goiter" but "is this particular nodule one of the few that isn't benign" — a question a genotype does not answer.
A 2026 study took an unusual approach: instead of scanning one thyroid disease at a time, it meta-analyzed genome-wide association data from 19 biobanks — including Penn Medicine BioBank, BioBank Japan and the UK's Genes & Health project — across five thyroid diseases together: thyroid cancer, benign nodular goiter, Graves' disease, lymphocytic thyroiditis and primary hypothyroidism. Drawing on roughly 2.9 million genomes in total, it found 313 already-known and 570 new independent loci across the five diseases combined. This page holds 22 of the variants specifically tied to benign nodular goiter.
Studying five diseases side by side let the researchers ask a question a single-disease study cannot: do these conditions share genetic architecture, and if so, how much? They found real genetic correlations between thyroid cancer, benign nodular goiter and the autoimmune thyroid diseases, ranging from 0.16 to 0.97 depending on which pair — a wide range that itself says something: these are not five names for one shared "thyroid disease" gene set, but five related, partly-overlapping ones.
The study proposes a specific answer to the question a nodule diagnosis actually raises: telomere-maintenance genes contributed to both benign and malignant thyroid nodular disease risk, while cell-cycle, DNA-repair and damage-response genes were associated specifically with thyroid cancer. Several genes among this page's 22 variants fit that pattern directly — DLGAP5, SGO2 and KNL1 all act in chromosome segregation during cell division, the same broad process telomere maintenance also governs. TG, the gene for thyroglobulin — the protein thyroid hormone is built from, and about as thyroid-specific a gene as exists — and GLIS3, a transcription factor needed for normal thyroid development, are also on this page, alongside metabolic genes shared more widely across endocrine traits (IRS1, JAZF1).
This site's thyroid cancer page draws on an earlier, thyroid-cancer-specific pair of studies. The genetic correlation this 2026 study found between the two diseases is a real, measured number — not a reason to read a benign-nodule genotype as cancer risk.
Benign nodular goiter is diagnosed by physical exam, ultrasound and thyroid function testing (TSH, T4) — not by genotype. None of the 22 variants on this page are used by any guideline to diagnose a goiter, or to decide whether a specific nodule needs a biopsy.
The loci described above are population-level GWAS findings from a meta-analysis of millions of genomes. They explain part of why goiter and nodule formation run in families and share biology with related thyroid conditions — they say nothing about whether, or how severely, any one person's thyroid will develop nodules, and nothing about whether an existing nodule is one of the few that is cancerous. That question is answered by ultrasound features and, when indicated, a fine-needle biopsy — not by anything on this page.
What a 23andMe/AncestryDNA export or raw VCF can and can't tell you about Benign Nodular Goiter comes down to these specific, well-studied positions — not a diagnosis.
Databases, guidelines and references
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Benign Nodular Goiter. MyGeneLog™. https://www.mygenelog.com/conditions/benign-nodular-goiter
Benign nodular goiter is an enlarged thyroid gland containing one or more non-cancerous lumps. It is extremely common, usually causes no symptoms, and is diagnosed by physical exam, ultrasound and thyroid function testing -- not by genetics.
Yes, measurably -- a 2026 study studying five thyroid diseases together found genetic correlations between benign nodular goiter, thyroid cancer and the autoimmune thyroid diseases ranging from 0.16 to 0.97 depending on the pair. That is a population-level statistic, not a reason to read an individual's benign-goiter genotype as cancer risk.
No. Whether a specific nodule is cancerous is determined by its ultrasound features and, when indicated, a fine-needle biopsy -- not by any variant on this page.
This page includes TG (thyroglobulin, the protein thyroid hormone is built from) and GLIS3 (needed for normal thyroid development), plus several genes -- DLGAP5, SGO2, KNL1 -- involved in chromosome segregation during cell division, fitting the source study's finding that telomere-maintenance biology contributes to both benign and malignant thyroid nodule risk.
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