ALPL and osteoporosis: Moreover, bone formation was inhibited when we generated alpl conditional knockout mice of BMSCs, which was consistent with recent reports.37 Further, other recent data have shown that increased marrow adipose tissue is correlated with dysfunction of bone and hematopoietic regeneration.38 We also found that bone formation was inhibited but adipose tissue was increased in the bone matrix of alpl conditional knockout mice, which suggests that ALPL regulates the osteogenic/adipogenic differentiation of BMSCs and causes osteoporosis in patients with HPP.