Bone manifestations in Snyder‐Robinson syndrome

Abstract

Purpose

Snyder-Robinson syndrome (SRS) is a rare, X-linked condition caused by loss of function variants in the SMS gene, which codes for spermine synthase, an enzyme essential for synthesis of the polyamine spermine [1]. It is speculated that polyamines are crucial for osteoblast activity [2]. While published cases of SRS have reported osteopenia or osteoporosis, the natural history of bone health in individuals with SRS has not yet been explored. It is hypothesized that the natural history of bone health in these individuals results in low bone density for age and increased fractures in the absence of intervention. It is important for healthcare providers to recognize bone manifestations in individuals with SRS so that an appropriate standard of care can be administered.

Methods

Case histories of 40 males with SRS spanning various ages from birth through adulthood were obtained from the Global Snyder-Robinson Syndrome Natural History Study and previously published cases. The data described and summarized in this study included dual x-ray absorptiometry (DEXA) scan results, fractures, and bisphosphonate treatment histories.

Results

Most individuals experienced at least one fracture, which was most common in their lower extremities. A greater number of fractures was reported when individuals did not receive bisphosphonates. Favorable DEXA results showed improvements in Z-scores and bone mineral density in individuals on bisphosphonates.

Conclusion

SRS is associated with persistent low bone density for age or osteoporosis. Treatment with bisphosphonates and long-term use requires further evaluation. This review contributes to the knowledge of bone health in the SRS population.