HNF1B and Rubinstein-Taybi syndrome: In addition, 15 participants had 1–2 severe medical conditions (extremely preterm: n = 4; neonatal hypoxia: n = 1; genetic condition: n = 5 (Deletion of HNF1-B and TCF2 genes, Rubinstein-Taybi syndrome, William-Buren syndrome, Fragile X, Down syndrome); metabolic condition: n = 1; seizure: n = 1; hemiplegia: n = 1; cerebral malformation: n = 1; early puberty: n = 1; pigmentary retinitis: n = 1).