Growth hormone treatment improves final height in children with X-linked hypophosphatemia

Background/aim: Despite optimal conventional treatment (oral phosphate supplements and active vitamin D analogs), about 40-50% of children with well-controlled X-linked hypophosphatemia (XLH) show linear growth failure, making them less likely to achieve an acceptable final height. Here, we studied the hypothesis that rhGH treatment improves final height in children with XLH and growth failure.Methods: Two cohorts of children with XLH were included in this retrospective longitudinal analysis: (1) a cohort treated with rhGH for short stature (n = 34) and (2) a cohort not treated with rhGH (n = 29). The mean duration of rhGH treatment was 4.4 +/- 2.9 years. We collected the auxological parameters at various time points during follow-up until final height.Results: In rhGH-treated children, 2 years of rhGH therapy was associated with a significant increase in height from- 2.4 +/- 0.9 to - 1.5 +/- 0.7 SDS (p < 0.001). Their mean height at rhGH discontinuation was - 1.2 +/- 0.9 SDS and at final height was - 1.3 +/- 0.9 SDS corresponding to 165.5 +/- 6.4 cm in boys and 155.5 +/- 6.3 cm in girls. Notably, the two groups had similar final heights; i.e., the final height in children not treated with rhGH being - 1.2 +/- 1.1 SDS (165.4 +/- 6.8 cm in boys and 153.7 +/- 7.8 cm in girls), p = 0.7. Conclusion: Treatment with rhGH permits to improve final height in children with XLH and growth failure, despite optimal conventional treatment. We propose therefore that rhGH therapy could be considered as an option for short stature in the context of XLH.