Cat Eye Syndrome and Der22 Syndrome

CES is a more rare disorder that the 22q11.2 deletion syndrome and it is associated with ocular colobomata, anal atresia, congenital heart defects, renal malformations, craniofacial anomalies, male genital anomalies, skeletal defects, and mild mental retardation (15,28). CES patients carry a supernumerary bisatellited chromosome 22, resulting in a tetrasomy of 22pter-

Fig. 1. Chromosome rearrangements on 22q11.2. To the left of the ideogram of chromosome 22, the list of human cancers breakpoint mapping in the 22q11q12 interval. On the right side, the list of the recurrent congenital anomaly disorders (dup(22)(q11.2; q11.2) disorder maps to the same interval as the 3 Mb VCFS/DGS deletion). Other duplication breakpoints occur more telomerically (not shown). The blue box represents the 3-Mb region associated with all three disorders. On the right, the horizontal line represents chromosome 22q11.2, with the centromere to the left. The recurrent chromosome rearrangement breakpoints are shown.

Fig. 1. Chromosome rearrangements on 22q11.2. To the left of the ideogram of chromosome 22, the list of human cancers breakpoint mapping in the 22q11q12 interval. On the right side, the list of the recurrent congenital anomaly disorders (dup(22)(q11.2; q11.2) disorder maps to the same interval as the 3 Mb VCFS/DGS deletion). Other duplication breakpoints occur more telomerically (not shown). The blue box represents the 3-Mb region associated with all three disorders. On the right, the horizontal line represents chromosome 22q11.2, with the centromere to the left. The recurrent chromosome rearrangement breakpoints are shown.

q11.2 (29-31). There are two common breakpoints in CES, type I and type II, and they occur in the same regions as for the common 3-Mb VCFS/DGS deletion breakpoints (26,31).

Der(22) syndrome is also a rare congenital anomaly disorder associated with similar features to CES, although there are some minor differences such as the absence of ocular colobomata and more severe mental retardation than in CES patients (32,33). Der(22) syndrome arises in offspring of normal carriers of the constitutional t(11;22) translocation, the most common recurrent non-Robertsonian constitutional translocation in humans (14). Patients with this disorder have a partial trisomy of the 11q23.3qter and 22pter-q11.2 regions (34,35). The recurrent t(11;22) translocation breakpoint occurs in the same region as for the 1.5 Mb distal deletion breakpoint in VCFS/DGS patients (Fig. 1), suggesting that this region is particularly labile (34).

Was this article helpful?

0 0

Post a comment