Kim et al. (2016) and Bae et al. (2016) observed that osteoporosis patients display a higher ratio of S1P in their plasma compared to bone marrow, with an additional study by Ardawi et al. (2018) finding a positive correlation between osteoporosis-related fracture and S1P plasma levels [64,65,66]. This evidence concerns the gene MBTPS1 and osteoporosis.