ESPE Abstracts

Background: The growth hormone-insulin-like growth factor (GH-IGF) axis plays a crucial role in bone growth, as evidenced by the phenotypes of patients with pathogenic IGF1 receptor (IGF1R) gene variants. These mutations lead to pre- and post-natal growth impairment and short stature. However, the molecular mechanisms of IGFs on human growth plate chondrocytes remain unclear, mainly due to the lack of tissue samples from healthy children.<p class=...

Background: Allan-Herndon-Dudley syndrome (AHDS) is an x-linked mental retardation syndrome characterized by severe psychomotor retardation and pathognomonic thyroid parameters. Defects in monocarboxylate transporter 8 (MCT8), which facilitates thyroid hormone (TH) uptake and efflux across plasma membranes, have been linked to this disease. The incidence of undescended testes was reported to be 8% by Schwartz et al. On the other hand, we had the impression that cryptorchidism ...

Object: IGF2 is a paternally expressed gene involved in the development of Silver-Russell syndrome (SRS). Here, we report six Japanese patients with IGF2 mutations and compare clinical findings between patients with IGF2 mutations including literature cases and those with H19/IGF2:IG-DMR epimutations.Patients: We recruited six Japanese patients with IGF2 mutations. Th...

X-linked hypophosphatemia (XLH) is characterized by excess FGF 23, hypophosphatemia, skeletal deformities, and growth impairment. Due to the lack of large-scale and long-term observational studies, not enough evidence has been accumulated to gain consensus on optimal care. A longitudinal, observational cohort study (SUNFLOWER) was initiated in Japan and South Korea to clarify the course of XLH; delineate its physical, mental, and financial burdens; and collect information on t...

In children with X-linked hypophosphatemia (XLH), excess circulating fibroblast growth factor 23 (FGF23) causes hypophosphatemia with consequent rickets, skeletal deformities, and impairments in growth and mobility. Compared to continuation with conventional therapy (oral phosphate and active vitamin D [Pi/D]), switching to treatment with burosumab, a fully human monoclonal antibody against FGF23, showed significantly greater improvement in phosphate homeostasis, rickets sever...

In children with XLH, high circulating levels of FGF23 cause hypophosphatemia with consequent rickets, skeletal deformities, and growth impairment. Conventional therapy consists of multiple daily doses of oral phosphate and active vitamin D (Pi/D). Burosumab is a fully human monoclonal antibody against FGF23 indicated for the treatment of XLH. In the active-control study CL301 (NCT02915705), 61 children with XLH (1–12 years old) were randomized (1:1) to receive subcutaneo...

In a randomized open-label phase 3 trial in 62 children (1–12 years) with X-linked hypophosphatemia (XLH) (NCT 02915705), switching from conventional therapy (oral phosphate plus active vitamin D) to burosumab, a monoclonal antibody targeting fibroblast growth factor 23, significantly improved serum phosphate concentration, rickets, lower-extremity deformities, growth, mobility, and patient-reported outcomes (PROs) at 64 weeks. Children in Europe, USA, Canada, and Australia wh...