SMAD9 and sclerosteosis: Mandible enlargement, torus palatinus, a tendency to sink when swimming, and an absence of adult fractures are reminiscent of LRP5 HBM.7, 48 Encouragingly, unlike sclerosteosis (due to anabolic SOST mutations) and some LRP5 HBM cases,9, 49 nerve compression was not a feature of SMAD9 HBM.