Genetic variant
rs921870045 a variant in the SEMA3B gene
rs921870045 is a single-letter difference in the SEMA3B gene, on chromosome 3. ClinVar, the public archive of variant interpretations, lists it as conflicting interpretations: laboratories that have assessed it do not agree on whether it matters. It has been reported in connection with SEMA3B-related disorder. Carrying it does not, on its own, mean you have or will develop any condition.
What is this?
Your DNA is a long sequence of four letters. At a few million positions, people commonly differ by a single letter; each of those positions is called a SNP (“snip”), and rs921870045 is the catalogue number of one of them, in the SEMA3B gene. Which letters you carry there — one copy from each parent — is your genotype.
SEMA3B (semaphorin 3B): The protein encoded by this gene belongs to the class-3 semaphorin/collapsin family, whose members function in growth cone guidance during neuronal development. This family member inhibits axonal extension and has been shown to act as a tumor suppressor by inducing apoptosis. Alternative splicing of this gene results in multiple transcript variants. [provided by RefSeq, Feb 2014]
Gene description from NCBI Gene
Why might it matter?
ClinVar records this variant as conflicting interpretations, meaning laboratories that have assessed it do not agree on whether it matters. A classification describes the variant, not you: what it means for one person depends on their genotype, their family history and often on other genes and circumstances.
Conditions it has been reported with
- SEMA3B-related disorder
Listed in ClinVar submissions for this variant. Being listed is a report of an association, not a statement that the variant causes the condition in any given person.
Do I have this variant?
If you have taken a consumer DNA test (23andMe, AncestryDNA and similar), you can download its raw data file and check. Create a free account, upload the file, and this page will show the letters you carry at rs921870045, if your test read this position.
Connect this with your blood results
A gene is a fixed instruction; a blood test shows what your body is doing now. CheckMyBloods reads the two side by side, so a variant can be set against the markers it could plausibly affect.
Blood markers do not diagnose a genetic condition, and a variant does not explain a blood result on its own. Together, with symptoms and family history, they give a clinician context.
What should I do next?
- Find out whether you carry it. Reading about a variant says nothing about you until you know your genotype.
- Put it in context. Add your blood results, so the variant can be read against what your body is doing.
- Ask questions. Dr. Hemsworth, our AI assistant, can explain this variant and your results in plain English.
- Take anything that worries you to a professional. A GP or genetic counsellor can order a confirmatory test and interpret it with your history.
This page is general information drawn from public research databases. It cannot diagnose anything, and it is not a substitute for advice from a doctor or genetic counsellor who knows your history.
Technical details
- dbSNP ID
- rs921870045
- Gene
- SEMA3B
- Position
- chr3:50273415
- ClinVar classification
- Conflicting classifications of pathogenicity
Sources
- dbSNP: rs921870045 — the reference record
- ClinVar — clinical interpretations submitted by laboratories
- SNPedia — community-written summaries
- NCBI Gene: SEMA3B
- Ensembl: SEMA3B