| The cri-du-chat syndrome (CDC, MIM123450), first described by Lejeune, is caused by deletions in 5p. Patients with this syndrome present with cat-like cry, microcephaly, a round face, hypertelorism, micrognathia, prominent nasal bridge, epicanthal folds, mental retardation, and multiple malformations.Clinical manifestations and cytogenetics findings of 106 CDC cases, which were from Niebuhr's laboratory in Denmark, were analyzed. The term "5p deletion syndromes" is proposed to encompass all the patients with 5p deletion, while CDC is used only for those with the Lejeune symptoms. The cri-du-chat syndrome is one of the 5p deletion syndromes. The 5p deletion syndromes are further divided into 8 types according to the presence or absence of 4 main clinical symptoms, namely, cat-like cry, facial features, mental retardation, and multiple malformations. A phenotype map of 5p was constructed. Region 5pl2-5p13.32 is responsible for severe mental retardation and multiple malformations; 5p13.32-5p13.33, 5p14.33-5pl5.13 and 5pl5.31-5pter are responsible for mild or moderate mental retardation; 5pl4 is a region with no or few genes; 5p15.13-5p15.2, for adult facial features, and 5p15.2-5p15.31, for cat-like cry and child facial features.Since cat-like cry is the most typical symptom of 5p deletion syndromes, and mental retardation is the most common symptom, these two symptoms were selected for further research. Further analysis of the deletion breakpoints of key patients for mapping the chromosomal regions involved in cat-like cry and mental retardation revealed that the region related to cat-like cry is defined by D5S713-D5S18 of 5p15.2, and the regions for mental retardation include D5S418 (5p12)-D5S19 (5p14) and D5S12 (5p15.3)-5pter. 5p-specific probes from these regions were then used to isolate 13 YACs from 5p YAC library to construct 3 YAC contigs.In order to isolate expressed sequences from these regions, two approaches were developed, cDNA selection with YAC-containing total yeast...
|
PDF Full Text Request