LRP5 and idiopathic juvenile osteoporosis: Two variants of LRP5—p.Val667Met (c.2047G>A, population frequency 0% to 5.3%) and p.Ala1330Val (c.4037C>T, population frequency 4.7% to 22%)—had a mild effect on BMD in large non‐selected European cohorts, although it was associated with a significant increased risk of fracture.3, 12, 13 Very few novel heterozygous pathogenic mutations with major effect were identified in children and adolescents with juvenile idiopathic osteoporosis.14, 15 These studies revealed several variants related to a large spectrum of bone fragility.