Cri du Chat Syndrome – Human with Cat-like Cry

Cri du chat syndrome is a kind of genetic disorder that occurs when a small part of chromosomal material is missing from a particular region on chromosome 5.

Overview of Cri du Chat Syndrome

In 1963, Dr. Jerome Lejeune first described Cri du chat syndrome. It is named for the cat-like cry made by the patients with this genetic disorder. In French, Cri du chat means “cry of the cat”. Or we can call this syndrome as “5p minus syndrome”. This is because there is small deletion of genetic material from the short “p” arm of chromosome 5 to cause this unusual genetic disorder.

Features of Cri du Chat Syndrome

There are many unusual features for the infants with Cri du chat syndrome.

i. Cat-like cry (the most classic feature)

ii. Unusual facial features

iii. Poor muscle tone (hypotonia)

iv. Small head size (microcephaly)

v. Mental retardation

vi. Low birth weight

vii. Slow growth

viii. Congenital heart defects

ix. Language difficulties

x. Delayed motor skill development

xi. Behavioral problems (childish)

Genetic Basis of Cri du Chat Syndrome

The high-pitched mewing cry during infancy is caused by defective development of the larynx (organ in the throat which produced voice). The deleted part of chromosome 5 is essential for normal development. As we all know, human have 46 chromosomes in every single cell of our body. At the same time, we should have two copies of chromosome 5. However, individuals with Cri du chat syndrome have lost a small part of chromosome 5. There is a small piece of material has been deleted from the “p” arm of one of the chromosome 5. On the other hand, the deleted chromosomal material consists of many important genes for normal development. Because of losing these essential genes, the larynx, brain and other parts of body cannot function normally. Generally, the deletion is sporadic (occurs irregularly).

Diagnosis of Cri du Chat Syndrome

Yet, the cat-like cry from children with Cri du chat syndrome will becomes less noticeable when they get older. Therefore, we can just identify and diagnose this syndrome if a child with younger age has this unusual mewing cry. Chromosome analysis or karyotyping can provide the definitive diagnosis of Cri du chat syndrome by staining the chromosome and examining them under a microscope. FISH (fluorescence in-situ hybridisation) is useful and effective to detect a small deletion in chromosome like Cri du chat syndrome.

Unfortunately, there is still no cure for this syndrome. Nevertheless, the medical experts can still provide the supportive care and development therapy to the patients to make the things better. Once the unusual features are under controlled, most of them can live normally.

In conclusion, although there is still no cure for Cri du chat syndrome, we can still lessen the symptoms by receiving the suitable therapy.

I have to apologise as I seldom to update this Cytogenetics and Cancer Research blog recently. I’m busying doing my final year project in University of Malaya. However, I will try my best to keep on updating the blog. Thanks!