Deletion of chromosome 1p36 is the most commonly observed terminal deletion in humans with a frequency of 1 in 5,000 in the general population. In contrast, 22q13 duplications are rare and only a few cases have been reported. Unbalanced translocations resulting in monosomy 1p36 and a trisomy of 22q13.3 are, thus far, unreported in the literature. Here we present the clinical data and the results of array CGH and FISH analysis of four patients with unbalanced translocations t(1;22)(p36;q13) inherited from unrelated balanced translocation carrier parents. The sizes of the imbalances ranged from 0.12 Mb to nearly 10 Mb. One balanced translocation carrier parent had disruption of the period homolog 3 (PER3) gene and reported sleep disturbances. Overall, patients tended to have more features consistent with deletion of 1p36 than duplication of 22q. © 2008 Wiley-Liss, Inc.