Duplication (17p) in a child with an isodicentric (17p) chromosome.

We present a child with multiple structural defects due to duplication of the short arm and a small portion of the long arm of chromosome 17. Three children with similar cytogenetic abnormalities have been reported previously. The karyotype contained an isodicentric chromosome derived from chromosome 17. A clue to the mechanism that produced the isochromosome was retained in the genome in the form of a part of the chromosome 17 long arm which was attached to the short arm of a chromosome 10.