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At a glance

This is a medical condition characterized by infants that have a cry that is similar to a meowing kitten as a result of laryngeal dysfunction. The clinical features include a high-pitched, cat-like cry in the newborn period, severe mental retardation, facial anomalies, scoliosis, muscular hypotonia, and congenital cardiac (eg, atrial and/or ventricular septal defects, tetralogy of Fallot, pulmonary stenosis, tricuspid regurgitation, patent ductus arteriosus, pulmonary hypertension) and renal defects (eg, horseshoe kidneys, renal ectopia, hydronephrosis). About one-third of children lose the cry by age of 2 years. Affected individuals may also present with cleft lip and palate, preauricular tags, thymic dysplasia, intestinal malrotation, and hypospadias.

Synonyms

Cat-Cry Syndrome; Lejeune Syndrome, Chromosome 5p Deletion Syndrome; 5p– Syndrome; Monosomy 5p.

History

First described in 1963 by the French geneticist Jèrôme Lejeune and colleagues at the University of Paris in three infants (two girls and a boy).

Incidence

Cri-du-Chat Syndrome (CdCS) is said to be the most common human deletion Syndrome, with an incidence of 1:15,000-50,000 live births. The frequency in patients with profound mental retardation (IQ<20) may be as high as 1%. A slight female predominance, but no differences with regards to ethnicity or geographical regions have been reported.

Genetic inheritance

CdCS arises from a partial or total deletion of the short arm of chromosome 5. A loss of the critical 5p15.2 region gives rise to most of the clinical features, while loss of region 5p15.3 seems to be responsible for the characteristic cry. The vast majority of cases are de novo occurrences with terminal (in 80-90%) or interstitial deletions (in up to 5%) of chromosome 5p, which in 80 to 90% are paternal in origin and most likely due to chromosome breakage during gamete formation in males. Some cases arise from unbalanced translocations or parental chromosomal rearrangements. There is wide phenotypic heterogeneity between patients with the same deletions, or even among affected family members. Descriptions exist of parents of affected children with 5p– deletions, who themselves have the same 5p– deletion, but lack any of the typical CdCS symptoms. The severity and prognosis of CdCS are influenced by the extent, location, and type of the chromosome deletion.

Diagnosis

Based on the clinical picture plus molecular cytogenetic confirmation of 5p deletion with fluorescent in-situ hybridization (FISH), which is considered the gold standard. Alternatively, comparative genomic hybridization (CGH) or quantitative polymerase chain reaction (PCR) can be used. Antenatal diagnosis with amniocentesis is possible.

Clinical aspects

The name of the syndrome stems from the characteristic, high-pitched, monotonous cry in infancy (it usually disappears after the first few months of life), which sounds similar to the meowing of a cat and is considered diagnostic for this disorder. However, a small subgroup of patients may exhibit the typical cry, but lack the frequent dysmorphic and developmental features of CdCS and have deletions that are limited to chromosome ...

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