Other genetic arrangements include a ring chromosome, where the chromosome loses a piece of information and the ends attach to form a ring, an interstitial deletion, where a section is deleted from the middle of the short arm and the broken ends rejoin, inversion, when a broken section flips before re-joining the chromosome, duplication, or very rarely, mosaicism, where the deleted chromosome is present only in some cells of the body. Children who are mosaic for Cri-du-Chat syndrome can be diagnosed for other conditions and syndromes by mistake. The portion of the deleted short arm that is the critical region for the main features except for the cry has been located to band 5p15.2, but the region for the cat-like cry is found on band 5p15.3. Thus, it is possible, though rare, to have the cry and no other features of Cri-du-Chat; conversely, it is possible to have most of the features of Cri-du-Chat, but not the cry.
The most distinguished feature of Cri-du-Chat appears in infancy. Babies with Cri-du-Chat emit a monotone, high-pitched wail that sounds like a cat. In fact, the syndrome is named after this phenomenon - Cri-du-Chat is the French phrase for "Cry of the Cat." Cri-du-Chat is also sometimes Cat Cry Syndrome.
In young children, Cri-du-Chat is also often characterized by failure to thrive, mental impairment ranging from severe to moderate, short stature (height lower than the 3rd percentile), infantile hypotonia and possibly poor muscle tone in childhood, sometimes an abnormal larynx, low birth weight, and rarely a congenital heart disease. The most prominent craniofacial manifestations are microcephaly (small head), a broad-based nose, micrognathia (small receding chin), poorly formed ears, malocclusion (widely spaced eyes) in older patients, and an abnormal palate (high or cleft); significant ocular manifestations include hypertelorism, epicanthic folds, and slanting eyes.
