Partial monosomy and partial trisomy for different segments of chromosome 13 in several individuals of the same family.

A reciprocal translocation, 46,XX,rcp(13;17)(q13;p13), was found to be segregating in a family. Two children have duplication of the distal portion of the long arm of chromosome 13, 46,XX,der(17),rcp(13;17)(q13;p13)mat. They are mentally retarded, have long philtra and postaxial hexadactyly. A maternal half-uncle has a duplication of the short arm and proximal portion of the long arm of chromosome 13, 47,XY,+der(13),rcp (13;17)(q13;p13)mat. He is mentally retarded, has scalp and skull defects and a very short philtrum. A fetus was found, on analysis of amniotic fluid cells, to have a deletion of the distal portion of the long arm of chromosome 13, 46,XX,der,(13),rcp(13;17)(q13;p13)mat. The fetus had multiple internal abnormalities and only 4 fingers on each hand.