A group of heart-rhythm disorders caused by the heart's own natural pacemaker malfunctioning — a 2021 GWAS found 4 genome-wide significant risk loci, one of them PITX2, this site's most-recurring atrial fibrillation gene.
Sick sinus syndrome is a group of heart-rhythm disorders caused by malfunction of the sinoatrial node, the heart's own natural pacemaker. It can cause an abnormally slow heart rate, pauses between beats, or alternating slow and fast rhythms, and is a common reason for pacemaker implantation, particularly in older adults.
This 2021 study compared 6,189 European-ancestry cases against 931,046 controls, and found 4 genome-wide significant loci, all represented on this page: rs7689774 (PITX2/MIR297, odds ratio 1.21, p=2×10⁻¹⁵), rs11554495 (KRT8, odds ratio 1.62, p=9×10⁻¹⁴, the strongest of the 4), rs12932445 (ZFHX3, odds ratio 1.16, p=8×10⁻¹⁰) and rs35813871 (TTN, odds ratio 1.13, p=6×10⁻⁹).
PITX2 is worth noting specifically: it is already this site's most-recurring locus for atrial fibrillation, a related but distinct arrhythmia — the "heart" topic page on this site notes that 15 of its own atrial fibrillation variants sit near PITX2. Finding the same gene here, for sick sinus syndrome, is a genuine cross-reference between two different rhythm disorders that share underlying biology, not a coincidence.
Sick sinus syndrome is diagnosed with an ECG or heart-rhythm monitoring that directly records the abnormal rhythm — not by genotype. None of the 4 variants on this page are used by any guideline to diagnose sick sinus syndrome or decide treatment in an individual.
Symptomatic sick sinus syndrome is typically treated with a pacemaker, which corrects the rhythm problem directly regardless of its underlying genetic contribution. The 4 variants on this page describe population-level susceptibility found in a very large research study; they do not change how an individual case is diagnosed or treated.
What a 23andMe/AncestryDNA export or raw VCF can and can't tell you about Sick Sinus Syndrome 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 4 of 4 linked studies with a resolved discovery ancestry.
Databases, guidelines and references
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Sick Sinus Syndrome. MyGeneLog™. https://www.mygenelog.com/conditions/sick-sinus-syndrome
Sick sinus syndrome is a group of heart-rhythm disorders caused by malfunction of the sinoatrial node, the heart's own natural pacemaker. It is a common reason for pacemaker implantation.
Comparing 6,189 cases against 931,046 controls, it found 4 genome-wide significant loci: PITX2/MIR297, KRT8, ZFHX3 and TTN, with odds ratios from 1.13 to 1.62 per copy.
PITX2 is already this site's most-recurring atrial fibrillation gene. Finding it again for sick sinus syndrome, a related but distinct arrhythmia, is a genuine cross-reference between two rhythm disorders that appear to share underlying biology.
No. Diagnosis requires an ECG or heart-rhythm monitoring that directly records the abnormal rhythm. Treatment is typically a pacemaker — not decided by genotype.
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