Trisomy for the Distal Segment of Chromosome 13

Abstract

Chromosome analysis with the Giemsa banding technique was performed in a child who had multiple congenital anomalies. A duplication of the distal one third of the long arm of chromosome 13 was found. This was traced to a pericentric inversion of a chromosome 13 and crossing-over within the meiotic inversion loop in the mother. A review of previously reported cases of partial trisomy for the distal segment of the long arm of chromosome 13 suggests the existence of a clinical entity distinct from the full trisomy.