Specifically, we aimed to explore associations between type 1 diabetes susceptibility polymorphisms mapped to vitamin D metabolism genes (CYP2R1, DHCR7, and CYP27B1) and anthropometric indices (weight, length, and skinfold thickness) or blood levels of endocrine regulators of growth (C-peptide, IGF-1, IGFBP-3, and leptin) in infancy. The gene discussed is CYP27B1; the disease is type 1 diabetes mellitus.