what is Microarray?
Microarray CGH: This method employs array elements that are prepared from large-insert genomic clones like BACs or phage artificial chromosomes (PACs). Its measurement precision allows reliable revealing of single-copy abnormalities affecting individual clones.
what is Skeletal radiography
This technique can highlight microcephaly, cranial base malformations such as lower cranial base angle or abnormally formed sella turcica and clivus, retromicrognathia, disproportionately short metacarpals (especially third, fourth and fifth) and disproportionately long proximal phalanges (especially second, third, fourth and fifth).
what is Chromosome comparative genomic hybridization
Chromosome comparative genomic hybridization (CGH): This technique is able to screen the whole genome for any DNA copy-number alterations in just a single hybridization. However, the results cannot be mapped directly to genome sequence and the resolution is restricted to around 5-10 Mb.
What is Fluorescence in situ hybridization (FISH)
FISH : This technique employs genetic markers which are precisely localized in our interested areas. Molecular cytogenetic studies along with FISH help in a better diagnosis of the very small deletions of 5p. if a fluorescent signal is absent from either paternal or maternal 5p chromosome regions, it is a clear indication of monosomy for that chromosomal region.
Diagnosis and work-up for Cri du Chat Syndrome
The high-pitched, monotone, cat-like cry is the basis of diagnosis during infancy. Other signs include poor muscle tone, microcephaly, micrognathia, hypertelorism, epicanthic folds and mental retardation. Chromosomal testing of the embryo, referring to when the child is still in the womb of the mother is a means of testing the syndrome. A diagnostic expert can perform tests on two samples in this stage, (1) chronic villus sampling (CVS), wherein a tissue sample from outer part of the sac where the child grows is tested and (2) amniocentesis, wherein a sample of amniotic fluid is tested.
After birth, a physical examination of the infant can disclose some abnormalities such as inguinal hernia, diastasis recti, separated abdominal muscles, or abnormally folded ears. An X-ray of the skull reveals an abnormal angle at the bottom. Some of the laboratory tests and tests that are performed for the diagnosis of the syndrome include
Conventional cytogenetic studies: The amount of the deleted chromosome differs from only 5p15 to the whole of the short arm. These studies are unable to detect a small deletion, but they are very useful.
High-resolution cytogenetic studies: Since small deletions are unable to be detected by conventional cytogenetic studies, high-resolution cytogenetic studies were performed to detect them.
Fluorescence in situ hybridization (FISH)
Chromosome comparative genomic hybridization (CGH) (http://cri-du-chat-syndrome.blogspot.com/)
Microarray CGH: This method employs array elements that are prepared from large-insert genomic clones like BACs or phage artificial chromosomes (PACs).
Apart from the chromosomal studies, imaging studies can also be helpful.
Skeletal radiography
MRI: This method is employed to detect atrophic brainstem, middle cerebellar peduncles or cerebellar white matter, hypoplasia of cerebellar vermis along with extra-growth of cisterna magna and fourth ventricle.
Echocardiography: This technique is employed to check if there are any structural cardiac abnormalities.
The other tests include swallowing study, developmental testing and evaluation of receptive and expressive language.
Treatment for Cri du Chat Syndrome
There is no specific treatment currently available for this syndrome. However, gene therapy may help in the infant stages but this is not 100% effective. No techniques or methods have been developed until now to treat large chromosome abnormalities. Gene therapy addresses some of the effects due to the gene deletion. The development of a good technique may take several more years and will not be available in the immediate future.
Most of the associated medical problems can be treated with the available medical treatments successfully. Mental retardation must be treated without fail. It is recommended for the parents to attend a genetic counseling. The parents must undertake a karyotype test to check if one parent has a genetic rearrangement in chromosome 5.
Early intervention programs through several therapies or educational strategies have been planned to enhance the physical, intellectual, sensory and social development in the children. These must include physiotherapy, speech and language therapy, occupational therapy and behavioral management when necessary. All these treatments according to surveys have been shown to improve the future stance of the child greatly.
These treatments are essential since most of the children affected with the syndrome undergo severe speech developmental problems. When the child is taught an alternative means for communication like a sign language, (eg. Makaton) in addition to a pictorial symbol system, this will improve the language acquisition and speech development. Cri Du chat
In most of the affected children, they are keenly interested in learning the communication and in fact, many can even develop their own language in the form of signs and gestures in order to get their requirements. In such cases, these children prefer to use their own language over the formal language taught by schools or doctors.
But some children may undergo a lot of frustration owing to their communication problems and this may lead to behavioral problems at times. Hence speech and language therapy is of significant importance and helps such children to develop their intellectual skills and improve the quality of their living greatly. In case, this is not possible at young ages, a communication device may be of tremendous help for older children and adults without adequate speech knowledge. (http://cri-du-chat-syndrome.blogspot.com/)
Apart from such programs, medical care attention is necessary for chronic problems like upper respiratory tract infections, severe constipation and otitis media. Visual-motor coordination computerized training can help in enhancing the visuospatial performance.
Surgical care is essential in the cases of congenital heart disease, temperature maintenance, anatomical abnormalities in airways, mental retardation, hypotonia, undescended testes, clubfoot, and strabismus. There is nothing like a special diet for such children. They may eat and drink everything like a normal person. Full-time care by parents may be necessary in children who are severely affected all through their lives in spite of the treatments.