A second group of 279 French children were selected from those referred to 2 centres (Laboratoire de Diagnostic Génétique, Nouvel Hôpital Civil, Strasbourg; Centre de Génétique Chromosomique, Hôpital Saint-Vincent de Paul, GHICL, Lille). Inclusion was based on obesity plus at least one Prader Willi-like syndromic feature (neonatal hypotonia and difficulty to thrive, mental retardation, developmental delay, behavioural problems, skin picking, facial dysmorphism, hypogenitalism or hypogonadism). Chromosomal abnormalities and Prader Willi Syndrome were excluded by karyotyping and DNA methylation analysis.
