Endocrine Abstracts

JOINT2412

Background: Hypophosphatemic rickets (HR) is a rare disorder characterized by impaired phosphate metabolism, leading to skeletal deformities, short stature, and delayed bone mineralization. While its impact on childhood growth is well-documented, its effect on pubertal development and final height remains unclear. This study aims to evaluate pubertal progression, final height outcomes, and associated clinical factors in HR patients to provide insights into optimizing growth management strategies.

Methods: This retrospective study included HR patients diagnosed either clinically or genetically. Data including pubertal onset, progression, final height, and pubertal height gain were collected. Height SDS and BMI SDS were analyzed across different Tanner stages. Statistical analyses were performed to assess the association between pubertal onset and final height, sex-based growth differences, and predictors of target height.

Results: A total of 34 patients (F/M:18/16) were included. Genetic analysis was available for 13 patients, with mutations identified in PHEX (n = 7), SLC34A3 (n = 4), SLC34A1 (n = 1), and DENT (n = 1). At presentation, the mean age of the patients was 8. 4±5. 2 years, and the mean height SDS was -2. 49±1. 56. The mean age at pubertal onset was 10. 6 (8. 4–13) years in females and 10. 7 (9. 4–15) years in males. The mean age at menarche was 13. 1±0. 8 years, which was significantly delayed compared to the Turkish population (12. 2±0. 9 years) (P < 0. 001). The pubertal height gain was 20. 1±6. 2 cmin girls and 29. 8±15. 4 cm in boys, comparable to that observed in the Turkish population. The duration of puberty was 5. 3±1. 0 yearsin girls and 5. 3±1. 5 years in boys. Among 13 patients (F/M:6/7), who reached final height, the final height SDS (-2. 3±1. 1) was significantly lower than the target height SDS (-1. 1±0. 9) (P = 0. 0005). The final height SDS was significantly higher in females compared to males (-1. 9±0. 9 vs. -3. 1±1. 1, P = 0. 045).

Conclusion: Despite a normal or slightly increased pubertal height gain in females, final height remained significantly below the genetic target in both sexes. Menarche was delayed, and pubertal duration was slightly prolonged in HR girls compared to the general population. Notably, females had a significantly higher final height SDS than males, suggesting a greater growth deficit in male patients despite comparable pubertal height gain. These findings underscore the importance of early intervention, continuous growth monitoring, and individualized treatment strategies to optimize final height outcomes in HR.