Co-occurrence of recurrent duplications of the DiGeorge syndrome region on both chromosome 22 homologues due to inherited and de novo events

Chromosome 22q11.2 duplication syndrome is associated with developmental delay and various birth defects and results when an individual has an extra piece (three copies total) of chromosomal material from 22q11.2. We describe five individuals who have an extra copy of this segment from 22q11.2 on both chromosome 22s (four copies total). The features seen in these individuals are similar to those seen in individuals with three copies. Although most of the individuals inherited the extra copies from both parents, one individual inherited an extra copy from the mother and the other extra copy occurred as a new (de novo) event in the father’s germ cell. (By Dr. Weimin Bi, http://jmg.bmj.com/content/early/2012/10/04/jmedgenet-2012-101002 )