Expressive

rs117688503 (FAM234B): Brain and Heart Expression

Key takeaways

  • rs117688503 modulates FAM234B expression in multiple tissues including the brain and heart.
  • The alternate allele increases expression in frontal cortex and heart, and decreases it in skin.
  • The frontal cortex association is among the most significant expression signals in the GTEx database.
  • The direction of effect is opposite in brain and heart versus skin, pointing to tissue-specific regulation.
  • No direct disease association for this variant has been reported in the available sources.

Key takeaways

  • rs117688503 modulates FAM234B gene expression across multiple tissues including the brain and heart.
  • The alternate allele increases FAM234B expression in the frontal cortex and heart, and decreases it in skin.
  • The frontal cortex association is among the most significant expression signals in the GTEx database, far exceeding standard genome-wide thresholds.
  • The direction of effect is opposite in brain and heart versus skin, pointing to tissue-specific regulation.
  • No direct disease association for this variant has been reported in the available sources.

What the research says Large-scale protein quantitative trait locus (pQTL) studies - which measure how genetic variants affect protein abundance in blood or biological fluids - have produced atlases connecting thousands of variants to proteins; a genome-proteome-wide study of 4,775 plasma proteins across 10,708 individuals identified 10,674 variant-protein associations and built a cis-anchored gene-protein-disease map covering 1,859 gene-protein-phenotype connections. A complementary cerebrospinal fluid (CSF) pQTL atlas of 6,361 proteins measured in 3,506 individuals identified 3,885 associations for 1,883 proteins including 2,885 not previously detected in blood-based studies, demonstrating unique genetic regulation in CSF with relevance to neurological conditions. Tissue-level expression data from GTEx v11 shows that rs117688503 specifically influences FAM234B expression across five tissues with a notably different direction depending on tissue type GTEx Portal.

Reported associations

  • FAM234B expression in brain frontal cortex (BA9): The alternate allele is associated with increased expression (effect slope +0.54, p=1.8e-15, 953 donors) GTEx Portal
  • FAM234B expression in brain cortex: The alternate allele is associated with increased expression (slope +0.33, p=3.7e-6) GTEx Portal
  • FAM234B expression in heart left ventricle: The alternate allele is associated with increased expression (slope +0.69, p=1.8e-6) GTEx Portal
  • FAM234B expression in non-sun-exposed skin (suprapubic): The alternate allele is associated with decreased expression (slope -0.29, p=4.0e-5) GTEx Portal
  • FAM234B expression in sun-exposed skin (lower leg): The alternate allele is associated with decreased expression (slope -0.23, p=1.3e-4) GTEx Portal

Evidence quality All five tissue associations for rs117688503 derive from GTEx v11 (953 donors, cis-window, FDR below 0.05) GTEx Portal. The frontal cortex BA9 signal (p=1.8e-15) far exceeds standard genome-wide significance thresholds; the heart left ventricle (p=1.8e-6), brain cortex (p=3.7e-6), and two skin tissue signals (p=4.0e-5 and p=1.3e-4) are each well-supported. The opposite direction of effect in brain and heart versus skin is a notable observation that suggests differential transcriptional regulation across tissue types, though the biological mechanism has not been characterized in the provided sources GTEx Portal. The broader pQTL studies measured thousands of proteins across tens of thousands of participants and establish the utility of this class of variant-protein mapping for disease biology, but neither reports a specific disease association for rs117688503 in the provided text. No replication in independent cohorts for disease outcomes is available in the provided sources.

Tissue-specific expression effects

  • FAM234B: Increased expression in brain frontal cortex (BA9), brain cortex, and heart left ventricle; decreased expression in both non-sun-exposed (suprapubic) and sun-exposed (lower leg) skin - the direction in brain and heart is opposite to the direction in skin GTEx Portal

Lifestyle considerations No lifestyle considerations on file for this variant.

Frequently asked questions

What does FAM234B do?

FAM234B (family with sequence similarity 234, member B) is a protein-coding gene expressed in the brain, heart, and skin. Its precise biological function remains under investigation; current evidence shows its expression is regulated differently depending on the tissue type.

What is rs117688503 associated with?

Based on available sources, rs117688503 is associated with differences in FAM234B gene expression across several tissues. The alternate allele links to higher expression in brain and heart and lower expression in skin. No direct disease association has been reported in the provided research.

What is an eQTL and why does it matter for this variant?

An eQTL (expression quantitative trait locus) is a genetic variant that influences how much a gene is expressed in a given tissue. rs117688503 acts as an eQTL for FAM234B in brain, heart, and skin based on GTEx data. eQTL effects describe molecular mechanisms, not confirmed health outcomes.

Is rs117688503 linked to brain or heart disease?

The provided research does not report a direct link between rs117688503 and any specific brain or heart disease. The variant influences FAM234B expression in frontal cortex and heart tissue, but the clinical significance of these expression changes has not been established in the available sources.

What are pQTLs and how do they relate to this variant?

A pQTL (protein quantitative trait locus) is a genetic variant that affects how much of a specific protein circulates in blood or other fluids. Large-scale pQTL studies have mapped thousands of variant-protein connections, providing a framework for understanding how variants like rs117688503 may connect to biology and disease.