Expressive

rs112780433 (FAF1): T2D and brain expression QTL

Key takeaways

  • This variant near FAF1 appeared in a Qatar Biobank GWAS examining type 2 diabetes in over 11,000 participants.
  • GTEx data shows the alternate allele reduces expression of CDKN2C (a cell-cycle regulator) in brain regions and skeletal muscle.
  • The same allele increases AGBL4 expression in the cerebellar hemisphere.
  • Expression effects span at least five genes across brain, nerve, muscle, and digestive tissues.
  • No variant-specific effect size for the T2D association is available from the provided study text, making this a preliminary finding.

Key takeaways

  • This variant near FAF1 appeared in a Qatar Biobank GWAS examining type 2 diabetes in over 11,000 participants.
  • GTEx data shows the alternate allele reduces expression of CDKN2C (a cell-cycle regulator) in brain regions and skeletal muscle.
  • The same allele increases AGBL4 expression in the cerebellar hemisphere.
  • Expression effects span at least five genes across brain, nerve, muscle, and digestive tissues.
  • No variant-specific effect size for the T2D association is available from the provided study text, making this a preliminary finding.

What the research says A genome-wide association study (GWAS, a method for scanning the genome to find variants linked to a trait) of type 2 diabetes (T2D) in Qatar sequenced 11,436 participants (2,765 T2D cases and 8,671 controls), replicating 93 known T2D-associated loci and extending the analysis through a trans-ethnic meta-analysis covering roughly 180,834 T2D cases and 1,159,055 controls from multiple ancestries. GTEx expression-quantitative trait locus (eQTL) data from 953 donors shows that the alternate allele at this locus is linked to reduced expression of CDKN2C (cyclin-dependent kinase inhibitor 2C, a protein that slows cell division) in cerebellar and skeletal muscle tissue, and to increased expression of AGBL4 (an enzyme that modifies tubulin, the structural building block of the cell skeleton) in the cerebellar hemisphere GTEx Portal.

Reported associations

  • Type 2 diabetes (research context): This locus falls within a Qatari GWAS of 2,765 T2D cases and 8,671 controls, plus a trans-ethnic meta-analysis of approximately 1.34 million individuals; the provided study text does not report a variant-specific effect size or p-value for rs112780433.
  • CDKN2C expression - brain cerebellar hemisphere: Reduced expression with the alternate allele (slope -0.33, p=2.3e-5) GTEx Portal.
  • CDKN2C expression - brain cerebellum: Reduced expression (slope -0.35, p=9.2e-5) GTEx Portal.
  • CDKN2C expression - skeletal muscle: Reduced expression (slope -0.25, p=3.6e-10) GTEx Portal.
  • AGBL4 expression - brain cerebellar hemisphere: Increased expression (slope +0.35, p=9.4e-5) GTEx Portal.
  • ENSG00000299346 expression - brain cerebellar hemisphere: Reduced expression (slope -0.75, p=6.7e-7) GTEx Portal.
  • ENSG00000299346 expression - tibial nerve: Reduced expression (slope -0.28, p=5.7e-4) GTEx Portal.
  • ENSG00000233406 expression - esophagus muscularis: Increased expression (slope +0.41, p=3.2e-5) GTEx Portal.
  • ENSG00000234080 expression - esophagus muscularis: Increased expression (slope +0.36, p=3.4e-4) GTEx Portal.

Evidence quality The T2D research context comes from a single GWAS of the Qatari population (11,436 participants; 2,765 cases and 8,671 controls) extended by a trans-ethnic meta-analysis covering approximately 1.34 million individuals from multiple ancestries. The provided study text does not report a variant-specific effect size or p-value for rs112780433 itself, limiting independent assessment of the strength of any T2D signal at this locus. The GTEx eQTL signals are derived from 953 donors at FDR less than 0.05; the strongest association in the provided data is CDKN2C expression in skeletal muscle at p=3.6e-10. The study authors note that Middle Eastern populations are historically underrepresented in GWAS research, which may limit the cross-population generalizability of findings from this cohort. No conflicting findings are present in the provided materials, though independent replication of any T2D association at this variant has not been demonstrated by the available evidence.

Tissue-specific expression effects

  • ENSG00000299346: Reduced expression in brain cerebellar hemisphere and tibial nerve with the alternate allele GTEx Portal.
  • CDKN2C: Reduced expression in brain cerebellum, brain cerebellar hemisphere, and skeletal muscle GTEx Portal.
  • ENSG00000233406: Increased expression in esophagus muscularis GTEx Portal.
  • AGBL4: Increased expression in brain cerebellar hemisphere GTEx Portal.
  • ENSG00000234080: Increased expression in esophagus muscularis GTEx Portal.

Lifestyle considerations No lifestyle considerations on file for this variant.

Lifestyle context

Concrete actions anchored to the cited research. We do not prescribe, we describe.

Diet

  • limit refined carbohydrates and added sugars Moderate

    Genetic predisposition to T2D is exacerbated by refined carbohydrates; they elevate post-prandial glucose and impair insulin sensitivity

    Prioritize whole grains, legumes, vegetables; limit sugary drinks and processed foods

Discuss with your doctor

  • discuss genetic T2D risk with healthcare provider Moderate

    Healthcare provider awareness of genetic risk enables personalized prevention strategies and closer monitoring for early disease signs

Exercise

  • regular aerobic exercise for T2D prevention Moderate

    Genetic risk for type 2 diabetes is substantially modifiable through lifestyle; aerobic exercise improves insulin sensitivity and reduces progression risk

    150 minutes per week of moderate-intensity aerobic activity or 75 minutes vigorous

Lifestyle

  • weight management for T2D risk reduction Moderate

    Excess body weight amplifies genetic T2D risk through insulin resistance; weight loss improves insulin sensitivity and glucose control

    Maintain BMI 18.5-24.9; if overweight, aim for 5-10% weight loss over 6-12 months

Screening

  • annual glucose and diabetes screening Moderate

    Genetic risk variant warrants earlier and more frequent screening to enable early diabetes detection and preventive intervention

    Fasting glucose and HbA1c testing annually; more frequently if prediabetic

Frequently asked questions

What is rs112780433 and which gene is it near?

rs112780433 is a genetic variant located near the FAF1 gene. It has been included in a genome-wide association study of type 2 diabetes in a Qatari population and shows tissue-specific effects on gene expression in brain, muscle, nerve, and digestive tissues according to GTEx eQTL data.

Is rs112780433 linked to type 2 diabetes?

This variant appears in the context of a GWAS that studied 2,765 type 2 diabetes cases and 8,671 controls from Qatar, extended by a trans-ethnic meta-analysis of over 1.3 million participants. The available study text does not report a variant-specific effect size for rs112780433, so the strength of any direct association remains unclear from current evidence.

What is CDKN2C and why is it relevant to this variant?

CDKN2C (cyclin-dependent kinase inhibitor 2C) is a protein that helps regulate cell division. GTEx data shows that carriers of the alternate allele at rs112780433 tend to have lower CDKN2C expression in brain regions and skeletal muscle, though the health implications of this expression change are not established by the current evidence.

Which tissues does rs112780433 affect according to GTEx?

GTEx eQTL data links this variant to expression changes in at least five tissue types: brain cerebellar hemisphere, brain cerebellum, skeletal muscle, tibial nerve, and esophagus muscularis. The effects involve five distinct genes, with direction of change varying by gene and tissue.

How strong is the evidence for rs112780433?

Evidence is preliminary. The strongest signal in the provided data is the CDKN2C expression effect in skeletal muscle at p=3.6e-10 from GTEx. The type 2 diabetes association comes from a single Middle Eastern cohort without a published variant-specific effect size in the available text, and the study authors note that this population has been historically underrepresented in genetic research.