Aliases: Cat cry Syndrome; Chromosome 5p- Syndrome; 5p Deletion Syndrome; Monosomy 5p; 5p- Syndrome
Gene(s) involved: Genes in the critical region of 5p15.2-5p15.3.
Brief description of disorder: Cri-du-chat syndrome is characterized by distinct facial features, microcephaly, hypotonia, mental retardation, developmental delay, low birth weight, single-palmar crease, and a high-pitched cry. Characteristic facies include hypertelorism, epicanthal folds, low set ears, micrognathia, and a round face. Associated findings include congenital heart disease, scoliosis, pes planus, absent kidney and spleen, clinodactyly, short neck, and perauricular skin tag.
The prevalence of Cri-du-Chat syndrome is approximately one in every 20,000 to 50,000. Females are affected slightly more often than males.
Inheritance pattern: Cri-du-Chat syndrome is most often the result of a de novo genetic mutation. Approximately 10% of cases are caused by segregation of a parental balanced location or pericentric inversions The cat-like cry has been mapped to chromosome 5p15.3, while the remaining syndromic features are associated with chromosome 5p15.2. Thus individuals with deletions of only 5p15.3 have the cat-like cry, with less severe dysmorphology and developmental delay.
Genetics: Cri-du-Chat is most likely caused by deletions of multiple genes on 5p. Terminal and interstitial deletions are the most common causes of this disorder. Deletions of the TERT gene have been associated with phenotypic changes, while deletions involving the CTNND2 gene have been associated with severe mental retardation in many Cri-du-Chat cases. Large deletions are associated with a more severe phenotype.
Test method: Conventional G-banded cytogenetic analysis, FISH, and array can be used to detect deletions and duplications.
Test sensitivity: Cytogenetic analysis detects approximately 25% of deletions that are greater than 5 Mb. FISH and aCGH will detect 98-100% of deletions/ duplications that are greater than 100 kb; however deletions/ duplications that are smaller than 100kb will not be detected by aCGH and deletions/ duplications that are smaller than the FISH probe will not be detected by FISH.
Specimen requirements for Cytogenetic Analysis, FISH, or Array:
Adult: 3-5 ml peripheral blood in a sodium-heparin tube.
Newborn: 1-3 ml blood in a sodium-heparin tube.
Turn-around-time
Newborns: 2-3 days
Non-STAT: 2-14 days
Array: 7-14 days
References
Medline
Genetics Home Reference
OMIM
Jones KL (2006). Deletion 5p Syndrome. In K.L. Jones (6th Edition), Smith’s Recognizable Patterns of Human Malformation (pp. 40-41). Philadelphia: Elsevier.
revised 5-24-2011
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