Genetic Mutations & Gene Therapy

What is Down Syndrome? 

Down syndrome (also called Trisomy 21) is a genetic disorder that occurs in approximately 1 of 800 live births. It is the leading cause of cognitive impairment. Down syndrome is associated with mild to moderate learning dissabilities, developmental delays, characteristic facial features, and low muscle tone in early infancy. Many individuals with Down syndrome also have heart defects, leukemia, early-onset Alzheimer's disease, gastro-intestinal problems, and other health issues (Citation 181).

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 What are the chromosome basics of Down syndrome?

Genes on an extra copy of chromosome 21 are responsible for all characteristics associated with Down syndrome. Normally, each human cell contains 23 pairs of different chromosomes. Each chromosome carries genes, which are needed for proper development and maintenance of our bodies. At conception, an individual inherits 23 chromosomes from the mother (through the egg cell) and 23 chromosomes from the father (through the sperm cell).

However, sometimes a person inherits an extra chromosome from one of the parents. In Down syndrome, an individual most often inherits two copies of chromosome 21 from the mother and one chromosome 21 from the father for a total of three chromosomes 21. Because Down syndrome is caused by the inheritance of three chromosomes 21, the disorder is also called trisomy 21. About 95% of individuals with Down syndrome inherit an entire extra chromosome 21.

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 Symptoms, Characteristics, & Features of Down Syndrome

Although the severity of Down syndrome ranges from mild to severe, most individuals with Down syndrome have widely recognizable physical characteristics. These include:

• -A flattened face and nose, a short neck, a small mouth sometimes with a large, protruding tongue, small ears, upward slanting eyes that may have small skin folds at the inner corner (epicanthal fold);
  
  
• -White spots (also known as Brushfield spots) may be present on the colored part of the eye (iris);
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• -The hands are short and broad with short fingers, and with a single crease in the palm;
  
  
• -Poor muscle tone and loose ligaments are also common; and
  
  
• -Development and growth is usually delayed and often average height and developmental milestones are not reached.
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 How often does Down syndrome occur?

CDC estimates that each year about 6,000 babies in the United States are born with Down syndrome. In other words, about 1 of every 691 babies born in the United States each year is born with Down syndrome.

What problems do children with Down syndrome have?

Babies and adults with Down syndrome can have physical problems, as well as intellectual disabilities. Every baby born with Down syndrome is different. In addition to the physical signs, some might have major birth defects or other medical problems. However, many people with Down syndrome live happy, productive lives well into adulthood.

Still, some physical problems associated with Down syndrome include:

• A birth defect of the heart
• Stomach problems, such as a blocked small intestine
• Celiac disease, a digestive disease that damages the small intestine so that nutrients from food are not absorbed well
• Problems with memory, concentration, and judgment, often called dementia
• Hearing problems
• Eye problems, such as cataracts or trouble seeing objects that are close by (far-sighted)
• Thyroid problems
• Skeletal problems

A person with Down syndrome can have an IQ in the mild-to-moderate range of intellectual disabilities. He or she also mighty have delayed language development and difficulties with physical coordination. 

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 Treatment:

While there are many treatments for Down syndrome, Down syndrome is not a condition that can be cured. However, there are treatments and therapies for the physical, medical and cognitive problems associated with Down syndrome. The goal of medical treatments in Down syndrome are to manage the medical conditions associated with Down syndrome, while early intervention and therapies help many people with Down syndrome live long productive lives (Citation 188). Click here for a full list of treatments and therapies.

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