A 17q12 chromosomal duplication associated with renal disease and esophageal atresia.

Chromosomal imbalance of the 17q12 region (which includes the HNF1B transcription factor) has recently emerged as a frequent condition. 17q12 deletion was found in patients with various renal abnormalities, diabetes mellitus (MODY type 5), genital tract or liver test abnormalities, while 17q12 duplication was identified in a subset of patients with autism, mental retardation, epilepsy and/or schizophrenia but no renal disorder. We report here two first-degree relatives carrying a 17q12 duplication and harboring various renal abnormalities (bilateral hypoplastic kidneys with vesico-ureteric reflux or multicystic dysplatic kidney with contralateral hyperechogenic kidney). Esophageal atresia (EA) type C was identified at birth in one patient while none had neurological disorder. Because EA has already been identified in patients with 17q12 duplication or HNF1B point mutation, we screened HNF1B (QMPSF and direct sequencing) in nine additional patients with EA and renal abnormalities but failed to identify any pathogenic variant. This is the second report of HNF1B mutation associated with EA. Moreover, we showed herein, that renal malformations may be part of the 17q12 duplication syndrome.