Quantile-specific heritability of serum growth factor concentrations

Area of Science:

• Genetics
• Molecular Biology
• Biostatistics

Background:

• Quantile-dependent expressivity describes how a genetic variant's effect size changes based on phenotype concentration (high vs. low).
• Understanding this phenomenon is crucial for interpreting genetic associations with complex traits.

Purpose of the Study:

• To investigate quantile-specific heritability of key growth factors: vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), angiopoietin-2, soluble Tie-2 receptor (sTie-2), and soluble fms-like tyrosine kinase-1 (sFlt-1).

Main Methods:

• Quantile-regression analysis was employed on family data from the Framingham Heart Study.
• Heritability (h) was assessed across different concentration percentiles for the selected growth factors.

Main Results:

• Heritability for VEGF, HGF, angiopoietin-2, sTie-2, and sFlt-1 significantly increased with higher percentiles of their respective distributions.
• This trend was statistically significant across all studied growth factors (Ptrend < 10-16 for VEGF).

Conclusions:

• Heritabilities of VEGF, HGF, angiopoietin-2, sTie-2, and sFlt-1 are indeed quantile-dependent.
• This quantile-specific heritability may elucidate previously reported interactions between genetic loci and conditions like metabolic syndrome, diet, and various diseases.