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#123450 CRI-DU-CHAT SYNDROME

TABLE OF CONTENTS

• DESCRIPTION
• CLINICAL FEATURES
• MOLECULAR GENETICS
• POPULATION GENETICS
• REFERENCES
• CREATION DATE
• EDIT HISTORY

DESCRIPTION    To Table of Contents

A number sign (#) is used with this entry because the cri-du-chat syndrome is a well-described partial aneusomy resulting from deletion of the short arm of chromosome 5.

Cri du chat syndrome was first described by Lejeune et al. (1963) as a hereditary congenital syndrome associated with deletion of part of the short arm of chromosome 5. The deletions can vary in size from extremely small and involving only band 5p15.2 to the entire short arm. Although the majority of deletions arise as new mutations, approximately 12% result from unbalanced segregation of translocations or recombination involving a pericentric inversion in one of the parents.  The syndrome is characterized in young children by microcephaly, round face, hypertelorism, micrognathia, epicanthal folds, low-set ears, hypotonia, and severe psychomotor and mental retardation. One of the most characteristic features in new born children is a high pitched cat-like cry that is usually considered diagnostic for the syndrome. However, a family has been described in which the characteristic cat-like cry was present without the morphological features (Baccichetti et al., 1988) and in which the deletion was confined to 5p15.32. Although the majority of patients die in early childhood, some survive into adulthood and exhibit an IQ below 20, a loss of hypertelorism and epicanthic folds and development of a thin narrow face with prominent nasal bridge.

MOLECULAR GENETICS    To Table of Contents

Overhauser et al. (1994) analyzed the 5p deletion breakpoints in 49 individuals using somatic cell hybrids. They used 5p-specific DNA probes to unambiguously order most of the chromosomal breakpoints present by hybridization to somatic cell hybrid DNA. Comparisons between the deletions present in the patients and their clinical features identified several chromosomal regions that were involved in specific clinical features. A critical chromosomal region involved in the high-pitched cry mapped to proximal 5p15.3 (probe D5S727), while the chromosomal region involved in the remaining features of the syndrome mapped to a small region within central 5p15.2 (probe D5S721). This latter region was estimated to be about 2 Mb in size. Deletions that did not include these 2 chromosomal regions presented varying clinical phenotypes from severe mental retardation and microcephaly to a clinically normal phenotype.  Gersh et al. (1995) studied 4 families in which patients with 5p deletions had only the characteristic cat-like cry, with normal to mildly delayed development. The precise location of the deletion in each family was determined by fluorescence in situ hybridization using lambda phage and cosmid clones. All of the deletion breakpoints mapped distal to a chromosomal region implicated with the facial features and severe mental and developmental delay in the cri-du-chat syndrome. The breakpoints were located distal to the 5p15.2 region and indicated that another genetic component of this contiguous gene syndrome is located in that area.

POPULATION GENETICS    To Table of Contents

The cri du chat syndrome appears to be one of the most common human deletion syndromes with an incidence varying between 1 in 20,000 to 1 in 50,000 births (Niebuhr, 1978). The frequency in populations of profoundly retarded patients (IQ less than 20) is approximately 1% (Niebuhr, 1978).

REFERENCES     To Table of Contents

1. Baccichetti, C.; Lenzini, E.; Artifoni, L.; Caufin, D.; Marangoni, P. :

Terminal deletion of the short arm of chromosome 5. Clin. Genet. 34: 219-223, 1988. Note: 89168805..

MEDLINE UID : 89168805
 

2. Gersh, M.; Goodart, S. A.; Pasztor, L. M.; Harris, D. J.; Weiss, L.; Overhauser, J. :

Evidence for a distinct region causing a cat-like cry in patients with 5p deletions. Am. J. Hum. Genet. 56: 1404-1410, 1995.

MEDLINE UID : 95282788
 

3. Lejeune, J.; Lafourcade, J.; Berger, R.; Vialatta, J.; Boeswillwald, M.; Seringe, P.; Turpin, R. :

Trois ca de deletion partielle du bras court d'un chromosome 5. C. R. Acad. Sci. (Paris) 257: 3098, 1963.

 

4. Niebuhr, E. :

The cri du chat syndrome: epidemiology, cytogenetics, and clinical features. Hum. Genet. 44: 227-275, 1978. Note: 79087397..

MEDLINE UID : 79087397
 

5. Overhauser, J.; Huang, X.; Gersh, M.; Wilson, W.; McMahon, J.; Bengtsson, U.; Rojas, K.; Meyer, M.; Wasmuth, J. J. :

Molecular and phenotypic mapping of the short arm of chromosome 5: sublocalization of the critical region for the cri-du-chat syndrome. Hum. Molec. Genet. 3: 247-252, 1994.

CREATION DATE     To Table of Contents

EDIT HISTORY

Forward to a letter written by parents that have a child with the Cri-du-chat disorder.
Forward to more information on Cri-du-chat.

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