Hypochondroplasia (HCH) is a skeletal dysplasia, mainly caused by mutations in the fibroblast growth factor receptor3 (FGFR3) gene and characterized by disproportionate short stature.
Our main was to determine the efficacy of growth hormone therapy in children with HCH, compared with a historical cohort of 40 untreated children with HCH.
Diagnosis of subjects was confirmed by the Bone Dysplasia Center2. Height standard deviation scores (SDS) were calculated from historical cohort-growth charts. Nineteen patients with initial height ≤=2 SDS were treated with Saizen® (r-hGH, Merck France) with an initial dose of 0.05 mg/kg/day (dose adjusted with IGF-I levels). We analyzed only 8 patients (4 males) treated during at least 5 years, at a mean age of 6.8 (± 2.6) yrs.
|Results||Baseline||1st yr||2nd yr||3rd yr||5rd yr||Total gain|
|Height velocity (cm/yr)||8.6±1.3||6.8±1.5||5.3±1.3||4.4±1.7|
|Height / HCP2 (SDS)||0.53±0.9||1.32±0.8*||1.91±1.1*||2.12±1.3*||2.10±1.1||1.57±0.8*|
|Upper segment (SDS)||−0.44±1.3||0.12±1.1*||0.46±1.3*||0.91±1.4*||0.99±0.9||1.43±1.2*|
|% Total fat mass (SDS)||1.33±0.9||0.30±0.4*||0.22± 0.8*||0.18±1.0*||0.52±1.1*||−0.81±0.8*|
|*P<0.01||1 vs Sempé; 2 vs values of a non-treated historical cohort HCH|
The height gain was +0.89 (± 0.60) SDS compared with French standard population (Sempé), but it was +1.57 (± 0.8) SDS with the historical cohort. Correlation in height gain was observed (P=0.04) between the first and fifth year. Difference in height gain between 5 patients with FGFR3 mutation (1.2 ± 0.8 SDS) and the 3 patients without (2.1 ± 0.6 SDS) was not significant (P=0.12). Seven patients reached near final height SDS: −1.67 ± 0.8 vs Sempé but +2.05 ± 1.1 vs the historical HCH cohort. No treatment related serious adverse-events were reported.
Conclusion: GH is effective in improving growth in some patients with HCH. Response during the first year is predictive of final response (r=0.78, P<0.05) and could be used to decide to continue treatment until final height.
19 - 21 Sep 2019
European Society for Paediatric Endocrinology