A male with two different familial autosomal fragile sites and a cytogenetically abnormal offspring

During the course of routine prenatal cytogenetics, a male with 2 different autosomal fragile sites (FS) was detected. The FS were at 9p21 and 12q13 and his sister also had both fragile sites, inherited from an obligate carrier father. He was the father of a foetus with an abnormal chromosome complement 46,XY/47,XY,+frag. The origin of the fragment could not be determined.