Mosaic Down Syndrome

Mosaic down syndrome is one of the various down syndromes that exist in today's world. As per statistics, almost 2 - 4% of children suffering from down syndrome, are affected by mosaic down syndrome. It is a genetic disorder that occurs or develops even before the child's conception. Each cell of the human body consists of 46 chromosomes, that is, 23 pairs of chromosomes that come from both the mother and the father. When a sperm fertilizes the egg, it starts multiplying further. A single cell contains 46 chromosomes, which is then divided into 2 cells, which further divide into 4, and so on. But at times, due to an error in the multiplication and division process of the cells, an extra copy of the 21st chromosome is found in one cell. Which means, that the cell, which ideally should have 46 individual chromosomes, now has 47 chromosomes, that is, it contains one copy extra of chromosome #21. This disorder is also known as Mosaicism. We shall discuss more about this syndrome as this article proceeds further.

Characteristics of Mosaicism

The symptoms in children start developing from a very early stage. The symptoms and characteristics vary right from their physical appearance, to mental health condition. Have a look at the mosaic down syndrome characteristics mentioned below.

• Mental retardation from mild to moderate level
• Risk of acquiring many chronic diseases like heart diseases, cancer, visual and auditory problems, and thyroid problems
• Flat nasal bridge
• Small chin
• Protruding tongue
• Neck is usually short in length
• Visible white spots on the iris
• Poor muscle tone
• Epicanthic fold in the inner eye corners
• Shortness in the limbs
• Huge visible gap between the large toe and the second toe
• The little finger has a single knuckle, wherein the finger appears to be flat
• Usually a child affected by Mosaic down syndrome has round face and a large forehead
• Speech problems

The IQ of children suffering from Mosaic down syndrome is visibly higher than the IQ level of children with typical Down Syndrome. Also another survey done by the Department of Human Genetics in the Medical College of Virginia, stated that the children with mosaicism are much more quicker than the children with typical down syndrome in terms of crawling, walking alone, etc.

Diagnosing Mosaic Down Syndrome

Mosaic down syndrome can be diagnosed even before the birth of the child through Chronic Villus Sampling. Even after the birth of the baby, genetic testing can be performed which helps determine the number of chromosomes present in the cell. On an average, Mosaic down syndrome is diagnosed in children aged between 1-4 years. The genetic takes account of a number of cells and checks the number of chromosomes present in each cell. For example, if 20-25 cells are counted through the genetic testing, and only 5 cells contain 46 chromosomes, while the rest contain 47 chromosomes, then the child is said to be suffering from high level of mosaicism. Many times, Mosaic down syndrome is misdiagnosed by trisomy 21.

Mosaic Down Syndrome makes the immune system very weak. Which is why, the population affected with this syndrome is prone to many infectious diseases. Other diseases may also attack the patient. It therefore becomes extremely important for the patient to be under constant medical supervision. There are many professional therapies like speech and language therapy, mental therapies, computer based therapies which can help the patient live with comparative ease. Constant love and support of the family members also contributes a lot in improving their quality of life.