Two siblings with Schaaf-Yang syndrome treated with growth hormone
Abstract
Schaaf-Yang syndrome (SYS) is a rare neurodevelopmental disorder with overlapping features with Prader-Willi syndrome (PWS). We report two Japanese siblings with SYS harboring a rare MAGEL2 variant (NM_019066.5:c.1621C>T, p.(Q541*)). Both patients had growth hormone (GH) deficiency and received GH therapy. The older sibling presented with neonatal hypotonia, joint contractures, and severe autism, while the younger sibling showed milder features but developed obesity and behavioral problems. GH therapy led to only modest improvement in their growth. The limited effect may have been related to the late initiation of treatment, marked non-adherence to therapy, and GH doses. This report highlights the phenotypic variability of SYS and demonstrates difficulties and potential issues of GH treatment as well as clinical response to GH treatment in this rare disorder.
Fields of Study & Subjects
Genetic Syndromes and Imprinting
Connective tissue disorders research
Neurogenetic and Muscular Disorders Research
Publication details
- Journal / source
- Clinical Pediatric Endocrinology
- Publisher
- Japanese Society for Pediatric Endocrinology
- Volume
- 35
- Issue
- 2
- Pages
- 186–191
- Publication date
- 1 January 2026
- Language
- EN