Context: Growth impairment in short stature homeobox-containing gene (SHOX) deficiency and Turner syndrome share a similar etiology. Because of the established effect of GH treatment on height in patients with Turner syndrome, we hypothesized that GH therapy would also stimulate growth in patients with SHOX deficiency.
Objective: Our objectives were to evaluate long-term efficacy of GH treatment in short patients with SHOX deficiency and to compare the effect on final (adult) height (FH) in patients with SHOX deficiency and Turner syndrome.
Design and setting: A prospective, multinational, open-label, randomized 3-arm study consisting of a 2-year control period and a subsequent extension period to FH. The treatment groups were 1) SHOX-D-C/GH (untreated during the control period, GH-treated during the extension), 2) SHOX-D-GH/GH, and 3) Turner-GH/GH (GH-treated during both study periods).
Patients: Short-statured prepubertal patients with genetically confirmed SHOX deficiency (n = 49) or Turner syndrome (n = 24) who participated in the extension.
Intervention: Depending on the study arm, patients received a daily sc injection of 0.05 mg/kg recombinant human GH from start of the study or start of the extension until attainment of FH or study closure.
Results: Height SD score gain from start of GH treatment to FH was similar between the combined SHOX-deficient groups (n = 28, 1.34 ± 0.18 [least-squares mean ± SE]) and the Turner group (n = 19, 1.32 ± 0.22). In this FH population, 57% of the patients with SHOX deficiency and 32% of the patients with Turner syndrome achieved a FH greater than -2 SD score.
Conclusions: GH treatment in short children with SHOX deficiency showed similar long-term efficacy as seen in girls with Turner syndrome.