Background: Pseudohypoparathyroidism 1A, newly classified as inactivating PTH/PTHrP signaling disorder type 2 (iPPSD2), is defined by resistance to parathyroid hormone, short stature and early-onset obesity. Short stature is caused by skeletal dysplasia and additionally, in some cases, also by the coexistence of growth hormone deficiency, as other hormonal resistances might be present (e.g. thyroid-stimulating hormone, growth hormone releasing hormone (GHRH), gonadotropins and calcitonin). Patients with iPPSD2 are often born with moderate intrauterine growth retardation. Hanna et al. (2018) showed that the average final height of patients lies <-2 SDS. Literature data on the effect of recombinant human growth hormone (rhGH) therapy for short stature in PHP1A children are sparse and there is no evidence regarding its influence on final height.
Objectives: Our multicentric, observational study describes growth patterns in PHP1A patients treated with rhGH compared to untreated controls.
Methods: We recruited 190 PHP1A patients from France, Italy and Spain. Twenty-six participants received rhGH for at least one year during the observed period, the rest did not. Birth history, height, weight and body mass index (BMI) at different time points, final height and pubertal stage the latter only during rhGH, were documented. We have analyzed the therapeutic effect of rhGH on final height on those patients, where pre-pubertal as well as final height measurements were available, by adjusting the comparison of rhGH-treated with untreated individuals for differences in mean pre-pubertal height standard deviation score (SDS) using a linear regression model.
Results: RhGH was started rather late (median age 9 years, range 2 to 14). In this group, 25% were born small for gestational age, comparable with the percentage seen in the control group (26%). Final height was available for 9/22 of rhGH-treated and for 45/164 of the participants that were not treated. We could show a gain in height SDS (mean± SD) after 1 year of rhGH (0.63± 0.52), as well as after 3 years of treatment (1.34±0.97). We could also show a clear beneficial impact of rhGH on final height: the difference in final height SDS between treated and untreated participants was of 1.36 (CI 0.59 - 2.14, P<0.002). BMI SDS did not vary between the two groups.
Conclusion: We show that rhGh treatment of iPPSD2 patients with short stature improves height and final height, but we recognize the need for more studies with data on final height.
15 Sep 2022 - 17 Sep 2022