A 12.4 Mb duplication of 17q11.2q12 in a patient with psychomotor developmental delay and minor anomalies.

We describe a 6-year-old boy with a de novo 12 Mb interstitial duplication of chromosome 17q11.1q12, identified by oligo array-CGH. The patient shows psychomotor developmental and language delay, dolicocephaly, minor facial anomalies, hypotonia and renal megacalicosis. The duplication involves the neurofibromatosis type I (NF1) gene and overlaps with long-range unusual deletions of the NF1 region, extending over 17q12 region and associated with renal cysts and diabetes (RCDA). To our knowledge this is the first case of a patient carrying a large-sized duplication involving the 17q11.2q12 region. In the duplicated chromosomal segment there are about 130 annotated genes. Among them, several genes which have been already proposed as candidate for mental retardation (MR) in patients with partially overlapping deletions may be responsible for neurological impairment in our patient. In addition, other genes within the duplicated region are of interest for possible correlation with a few clinical features of the patient.