In the validation cohorts, carriage of two APOL1 variant alleles (8.7% in OI+ vs. 14.2% in OI−) was recessively associated with 36% lower odds of OI (combined OR 0.64, 95% CI 0.45–0.91, P = 0.006, Table 3). The gene discussed is APOL1; the disease is osteogenesis imperfecta.