As reported before, defects of WNT1 cause diseases with a semidominant inheritance pattern.26, 27 Biallelic variants, as compound heterozygous or homozygous alleles, in WNT1 can cause OI type XV,26, 27, 28 an OI AR disease trait, whereas heterozygous variants can cause early‐onset osteoporosis as an apparent AD disease trait.27, 28 We identified rare variants in WNT1 associated with low BMD, implicating WNT1 variants in osteoporotic pathophysiology. Here, WNT1 is linked to osteoporosis.