Cri du Chat Syndrome, 5p-

Dr. Lejeune

Dr. Lejeune of Paris, France, was a physician, pro-life pediatrician and Doctor of Science and Professor of Genetics for 25 years. Dr. Lejeune discovered the genetic cause for Down’s Syndrome,    best known for his discovery of the link of diseases to chromosome abnormalities. He developed the karyotype (Karyotypes describe the number of chromosomes, and what they look like under a light microscope).  He had made his career specializing in the treatment of children with Trisomy 21, also called Down Syndrome. He also diagnosed the first case of Cri du Chat syndrome, 5p deletion syndrome or Cat cry syndrome and so named because of the distinctive cry in infancy that resembles the mewing of a cat in 1963.

Dr. Lejeune died April 3, 1994.

What is Cri du Chat Syndrome?      

 Cri du Chat syndrome (CDCS) refers to a unique combination of physical and mental characteristics associated with a loss of genetic material on the distal short arm of the fifth chromosome. Also called 5p- syndrome, 5p monosomy, or Cat Cry syndrome. Cri Du Chat  is a rare chromosome disorder affecting approx 1 in 37,000-50,000 live births. The syndrome is known to result from a deletion in the short arm of chromosome 5 and represents one of the most common deletion syndromes in humans. This condition is found in people of all ethnic backgrounds and is slightly more common in females.

They result from a chromosomal deletion that occurs as a random event during the formation of reproductive cells (eggs or sperm) or in early fetal development. Humans usually have 23 pairs of chromosomes in each cell of their body. These are named in pairs 1,2,3,4,5,6 etc. A chromosome consists of smaller components called genes which contain instructions in a code made up of proteins. This code contains the plans or blueprint for each human being. When something goes wrong with the chromosome in the process of creating a new human being, the code cannot be read properly and the child’s body and brain may not develop correctly. When a problem results from this genetic mistake it is called a genetic disorder.

Cri du chat syndrome is a genetic disorder; it is not an illness or a disease therefore there is no cure. A child born with this disorder has specific physiological problems which can result in their development being delayed both physically and intellectually. They may also have health problems because parts of their physiology have not developed correctly. Remember, nothing the parents have done has caused this deletion to occur.

Affected people typically have no history of the disorder in their family but there is a small percentage that can be carriers. The size of the deletion varies among affected individuals; studies suggest that larger deletions tend to result in more severe intellectual disability and developmental delay than smaller deletions in people with cri-du-chat syndrome.

Most common symptoms of Cri du Chat are:  Feeding problems because of difficulty swallowing and sucking accompanied by low birth weight and poor growth. Laryngeal structural differences, microcephaly (smaller than normal head), hypotonia (low muscle tone),  hypertelorism with the eyes (abnormally increased distance between two organs or body parts), epicanthic fold (a skin fold of the upper eye lid, covering the inner corner of the eye), down slanting palpebral fissure (separation between the upper and lower eyelids), gastroesophageal reflux, constipation, respiratory complications, scoliosis (curvature of the spine),  strabismus (a condition in which the eyes are not properly aligned with each other), flat nasal bridge, down turned mouth, micrognathism (undersized jaw), low set ears, single palmar crease (single crease that extends across the palm of the hand), frequent sinus, ear and respiratory infections and cardiac defects.

There are more severe yet less common symptoms if you would like more detailed information click here. Cri du Chat ABC Booklet  (it takes a moment to load)

 Individuals with Cri du Chat Syndrome have to overcome alot of challenges but with the right intervention and support can live happy

healthy lives.

New research on the Gene CTNND2

The CTNND2 gene provides instructions for making a protein called delta-catenin. This protein is active in the nervous system, where it likely helps cells stick together (cell adhesion) and plays a role in cell movement. In the developing brain, it may help guide nerve cells to their proper positions as part of a process known as neuronal migration. In mature nerve cells, delta-catenin is located in specialized outgrowths called dendrites. Dendrites branch out from the cell and receive information from nearby nerve cells. This information is relayed across synapses, which are junctions between ner

ve cells where cell-to-cell communication occurs. Delta-catenin appears to play a crucial role in the function of synapses.

How are changes in the CTNND2 gene related to health conditions? cri-du-chat syndrome – associated with the CTNND2 gene

The CTNND2 gene is located in a region of chromosome 5 that is often deleted in people with cri-du-chat syndrome. As a result of this deletion, many people with this condition are missing o

ne copy of the CTNND2 gene in each cell. The loss of this gene may cause severe intellectual disability in some affected individuals. Researchers suspect that intellectual disability could result from a disruption of neuronal migration during the early development of the nervous system. People with cri-du-chat syndrome who do not have a deletion of the CTNND2 gene tend to have milder intellectual disability or normal intelligence

The CTNND2 gene is located on the short (p) arm of chromosome 5 at position 15.2. More precisely, the CTNND2 gene is located from base pair 10,971,951 to base pair 11,904,109 on chromosome 5.                                                 

Sophie’s deletion is quite large, she has a heterozygous deletion which starts at bands p13.3-p (highlighted in red)  and extends to the rest of the chromosome with a 32.42 megabase deletion.

Which is easier to say about 75% of her short arm is missing.  According to the geneticist’s she should not be functioning the way she is with a deletion this size and her health history.

Doctors are amazed at her progress!

Doctors only know so much. Had I given up hope when we were told she would most likely not survive and if she did she would not have the capacity to function I know we would where we are at today, fighting to overcome and learn everyday. 

Then your light shall break forth like the morning, 

Your healing shall spring forth speedily,

And your righteousness shall go before you; 

The glory of the LORD shall be your rear guard.

Isaiah 58:8