Maternal complex chromosome rearrangements involving five chromosomes 1, 4, 10, 12 and 20 ascertained through a del(4)(p14p15) detected in a mother's first affected daughter.

Complex chromosomal rearrangements, defined as exchanges between three or more chromosomes, are very rare aberrations in human chromosomal pathology. We present a case of a complex, apparently balanced maternal chromosome rearrangement involving five different chromosomes (1, 4, 10, 12 and 20) and six breakpoints ascertained through a deletion of the short arm of chromosome 4 [del(4)(p14p15)] detected in a mother's affected 2-year old daughter.