ESPE Abstracts (2015) 84 P-1-141

Adult Height after Growth Hormone Treatment and its Association with X Chromosome Dosage in Turner Syndrome: a Cross-Sectional Database Analysis of the French National Rare Disease Network

Elodie Fiota, Delphine Zenatya, Priscilla Boizeaub, Jérémie Haignereb, Sophie Dos Santosa, Juliane Légera & FrenchTurner Syndrome Study Groupc

aPediatric Endocrinology and Diabetology, Robert Debré Hospital, Assistance Publique-Hôpitaux de Paris, Reference Center for Rare Diseases of Growth, Université Paris-Diderot, Paris, France; bClinical Epidemiology Unit, Robert Debré Hospital, Assistance Publique-Hôpitaux de Paris, Université Paris Diderot, Paris, France; cFrench Turner Syndrome Study Group, France, France

Background: In Turner syndrome (TS), Shox haploinsufficiency accounts largely, but not entirely, for the short stature of patients, which has been estimated at a mean loss of 20 cm with respect to target height. GH treatment has been shown to improve adult height (AH), although individual outcomes vary markedly. Little is known about the relationship between the dosage effects of the X-linked gene and responsiveness to GH.

Objective: To determine whether AH deficit with respect to target height (TH) after GH treatment is associated with karyotype subgroup.

Method: TH minus AH (SDS) was analyzed, by karyotype, after a median of 5.8 (3.6;8.5) years of GH treatment at a median dose of 50 μg/kg/day, in a national cohort of 465 patients with TS, with all karyotype groups treated similarly.

Results: Height before treatment and AH deficit with respect to TH SDS after GH treatment were associated with karyotype subgroup. Patients with structural abnormalities of the X chromosome (isoXq and ring X formation) or monosomy X were more severely affected than patients with mosaicism or with a Y chromosome.

Conclusion: These data suggest that haploinsufficiency for unknown Xp genes increases the risk of a larger AH deficit with respect to TH both before and after GH treatment in TS.