CYP11B1 variants influence skeletal maturation via alternative splicing

Abstract

We performed genome-wide association study meta-analysis to identify genetic determinants of skeletal age (SA) deviating in multiple growth disorders. The joint meta-analysis (N = 4557) in two multiethnic cohorts of school-aged children identified one locus, CYP11B1 (expression confined to the adrenal gland), robustly associated with SA (rs6471570-A; β = 0.14; P = 6.2 × 10⁻¹²). rs6410 (a synonymous variant in the first exon of CYP11B1 in high LD with rs6471570), was prioritized for functional follow-up being second most significant and the one closest to the first intron-exon boundary. In 208 adrenal RNA-seq samples from GTEx, C-allele of rs6410 was associated with intron 3 retention (P = 8.11 × 10⁻⁴⁰), exon 4 inclusion (P = 4.29 × 10⁻³⁴), and decreased exon 3 and 5 splicing (P = 7.85 × 10⁻⁴³), replicated using RT-PCR in 15 adrenal samples. As CYP11B1 encodes 11-β-hydroxylase, involved in adrenal glucocorticoid and mineralocorticoid biosynthesis, our findings highlight the role of adrenal steroidogenesis in SA in healthy children, suggesting alternative splicing as a likely underlying mechanism.

Olja Grgic, Matthew Gazzara, and Alessandra Chesi et al. perform a genome-wide association study meta-analysis for skeletal age in two pediatric cohorts. They observe that variation in the adrenal gene, CYP11B1, impacts its alternative splicing, suggesting that adrenal steroidogenesis may contribute toward variation in skeletal age in otherwise healthy children.