Confirmation of a de novo duplication, dup(10)(q24 leads to q26), by GOT1 gene dosage studies.

A girl with mental retardation and the facies associated with the distal 10q duplication syndrome was found to have a tandem duplication of 10q24 to 10q26. This was confirmed by gene dosage studies of glutamic oxaloacetic transaminase 1. The clinical features of this patient are compared with those of other reported cases of the distal 10q duplication syndrome with duplication-deficiency karyotypes due to familial reciprocal translocations or inversions or with tandem duplication of a more proximal region of 10q. Reports of tandem duplications in man and possible mechanisms of origin are discussed.