Growth Hormone Treatment in Patients With KBG Syndrome: Novel Insights, Challenges and Recommendations From Six New Patients and Literature Review.

KBG syndrome is one of the most frequent neurodevelopmental disorders and is caused by ANKRD11 variants. Postnatal short stature is observed in ~50% of patients. Recombinant human growth hormone (rhGH) has become a valuable treatment for patients with growth hormone deficiency (GHD) along with Prader-Willi and Turner syndrome. Limited evidence suggests benefits for some patients with KBG syndrome, but systematic analysis and detailed phenotyping are lacking. In this study, we include six unpublished patients with KBG syndrome treated with rhGH and 22 patients from the literature. At treatment start, 43% had GHD. Median height before treatment was -2.9 standard deviation score (SDS) which increased to -1.8 SDS at the latest measurement. Moreover, half of the patients showed height gains of ≥ 1 SDS and 10/18 patients with short stature before treatment achieved heights within normal ranges following treatment or at the latest available measurement. Of interest, the difference between pre-treatment height SDS and that at the latest measurement (∆HSDS) was comparable for patients with and without GHD. This study represents the largest group of patients with KBG syndrome treated with rhGH so far and suggests that rhGH treatment has a positive impact on height, as indicated by ∆HSDS, in a subset of patients.