Teeth that never form, not teeth that come in late — a different question from this site's tooth-eruption-timing page. A study of nearly 2,000 people with congenitally missing teeth found nine risk variants, several of them specific to which particular teeth go missing.
Tooth agenesis is the congenital absence of one or more teeth — they never develop, distinct from a tooth that is simply late to erupt. Excluding the third molars (wisdom teeth, which are commonly and separately absent), it is one of the most common developmental anomalies in humans, and it can run in families in a way that suggests a real genetic component beyond chance.
The study behind this page compared 1,944 people with congenitally missing teeth against 338,554 controls, all of European ancestry — testing both for genome-wide risk and for whether previously known variants linked to eruption timing or to orofacial clefts also mattered here. It found 9 novel risk variants for tooth agenesis overall, and identified that 5 of those specifically raise risk for selective agenesis — missing teeth in a particular, non-random pattern rather than broadly.
rs121908120, in WNT10A, is this page's variant for tooth agenesis generally — WNT10A is already known from earlier candidate-gene work (guided by mouse knockout studies, as the paper notes) as central to tooth development. Two further variants are specific to which teeth go missing: rs917412, near LEF1, for agenesis of the mandibular second premolars, and rs55846652, in EDA, for agenesis of the maxillary lateral incisors — the same gene already implicated in a range of ectodermal-development conditions, including some of the orofacial-clefts risk the study also tested against.
Tooth agenesis is diagnosed by clinical and radiographic examination — a dentist can see which teeth are present and which are missing, well before this or any genetic test would add information. Management depends on how many and which teeth are affected: options range from orthodontic space closure to prosthetic replacement (bridges, implants or dentures), planned by a dentist as part of an interdisciplinary approach, as the study's own authors note.
Not the same as slow eruption. A tooth that is simply late is a different, usually less consequential, situation from a tooth that never formed — see this site's own tooth eruption timing page for that separate question, and a dentist or orthodontist for which situation applies to a specific case.
What a 23andMe/AncestryDNA export or raw VCF can and can't tell you about Tooth Agenesis comes down to these specific, well-studied positions — not a diagnosis.
The studies behind these variants recruited participants from different ancestries — a result found in one population doesn't always transfer to another. Based on 3 of 3 linked studies with a resolved discovery ancestry.
Databases, guidelines and references
No. Tooth agenesis means a tooth never formed at all. A tooth that is simply late to erupt is present and developing — see this site's separate tooth eruption timing page for that question.
No. The pattern-specific variants here (for mandibular second premolars or maxillary lateral incisors) describe associations found across large groups of people, not a prediction for one individual. A dental examination shows directly which teeth are present.
Management depends on how many and which teeth are affected, and is planned by a dentist — options include orthodontic space closure or prosthetic replacement such as implants, bridges or dentures. Nothing on this page changes that process.
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