A rare chromosomal anomaly syndrome resulting from the partial duplication of the long arm of chromosome 22 with variable phenotype. Principle characteristics are varying degrees of intellectual disability and developmental delay, pre and postnatal growth deficiency, hypotonia, and craniofacial dysmorphism (microcephaly, hypertelorism, narrow and upslanted palpebral fissures, epicanthic folds, low-set dysplastic ears, broad and depressed nasal bridge, cleft lip an/or palate, long philtrum, retro/micrognathia). Congenital heart defects, as well as cerebral, skeletal, renal and genital anomalies have also been reported. [from SNOMEDCT_US]