De novo interstitial direct duplication 1(q23.1q31.1) in a fetus with Pierre Robin sequence and camptodactyly.

Interstitial duplications of chromosomal region 1q are rarely seen. We report the first prenatal diagnosis of pure partial trisomy 1q. The fetus was karyotyped for polyhydramnios, micrognathia, and flexion of fingers of both hands. Conventional and molecular cytogenetics showed a de novo direct duplication of the chromosomal region 1q23.1q31.1 leading to a partial trisomy 1q. At autopsy, the fetus showed Pierre Robin sequence (PRS) and camptodactyly. The main histological finding was a decreased number of motoneurons with apoptotic features in the anterior horn of the spinal cord. A literature review and our observations suggest that genetic material mapping to chromosome 1q25 could be responsible for PRS with distal arthrogryposis when this is in triple dose.