Midterm results of an open-label, single-center, nonrandomized, 2003-2020 pilot trial to final stature, including 6 children (mean age, 2.6 ¡À 0.7 years; mean height SDS, ?3.0 ¡À 0.5) with the N540K mutation of FGFR3 gene who received an rGH dosage titrated to an IGF-1 level close to 1.5 SDS of the normal range. rGH therapy was interrupted 1 day per week, 1 month per year, and 6 months every 2 years.
The mean height SDS increased by 1.9 during the 6.1 ¡À 0.9-year study period, reaching ?0.8 to ?1.3 at?age 8.7 ¡À 1 years. The mean ¡À SDS baseline IGF-1 value was ?1.6 ¡À 0.5 before rGH treatment and 1.4 ¡À 0.3 during the last year of observation. The average cumulative rGH dose was 0.075 ¡À 0.018 mg/kg/day (range, 0.059-0.100 mg/kg/day). Trunk/leg disproportion was improved.
IGF-1-dosing rGH treatment durably improves growth and reduces body disproportion in children with severe forms of hypochondroplasia.