Cri-du-chat syndrome

The answer is e. (Murray, pp 812-828. Scriver, pp 3-45. Sack, pp 57-84. Wilson, pp 123-148.) Children with chromosome abnormalities often exhibit poor growth (failure to thrive) and developmental delay with an abnormal facial appearance. This baby is too young for developmental assessment, but the catlike cry should provoke suspicion of cri-du-chat syndrome. Cri-du-chat syndrome is caused by deletion of the terminal short arm of chromosome 5 [46,XX,del(5p), also abbreviated as 5p—] as depicted in panel e. When a partial deletion or duplication like this one is found, the parents must be karyotyped to determine if one carries a balanced reciprocal translocation. The other karyotypes show (a) deletion of the short arm of chromosome 4 [46,XY,del(4p) or 4p—] (b) XYY syndrome (47,XYY) (c) deletion of the long arm of chromosome 13 [46,XX,del(13q) or 13q-] (d) Klinefelter s syndrome (47,XXY). Most disorders involving excess or deficient chromosome material produce a characteristic and recognizable phenotype (e.g., Down s, cri-du-chat, or Turner s syndrome). The deletion of 4p- (panel A) produces a pattern of abnormalities (syndrome) known as Wolf-Hirschhorn syndrome deletion of 13q- produces a 13q— syndrome (no eponym). The mechanism(s) by which imbalanced chromosome material produces a distinctive phenotype is completely unknown. 

Congenital adrenal hyperplasia Congestive heart failure Chromosome disorders Chromosome mosaicism Chromosome translocation Copper excess Cri-du-chat syndrome Crouzon s syndrome Cushing s syndrome Cyanide poisoning Cystic fibrosis Diabetes insipidus Diabetes mellitus Dinitrophenol poisoning Diphtheria... 

It is generally accepted that chromosome translocation occurs as a result of a double chromosomal break one at the side of the donor chromosome, and one at the side of the receptive chromosome. Such breaks are believed to yield sticky ends that facilitate the agglomeration of the translocated portion of the chromosome. Occasionally, during translocation a chromosome or a portion of the chromatin is lost. For example, cri-du-chat syndrome is believed to result from the loss of the short arm of chromosome 5. Loss of the short arm of chromosome 4 and of the short arm of chromosome 18 have been described and are associated with symptoms somewhat different from what is observed in the typical cri-du-chat syndrome (see Fig. 3-71). 

Fig. 3-71. Karyotype of female with partial deletion of the short arm of chromosome 5, the usual change in the cri-du-chat (cat s cry) syndrome. (From R. Sparkes)...

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