Down syndrome is a rare genetic disorder that occurs in 1 out of every 800 live births. Besides Cognitive impairment, the disorder is characterized by learning disabilities, delay in mental and physical development, distinctive facial features and low muscle tone during early infancy. Many of the patients with Down syndrome also develop secondary ailments like heart defects, gastro-intestinal problems, leukemia, early onset of Alzheimer’s disease and many other physiological and psychological health issues.
Down Syndrome Facts
1 in every 900 babies are born with Down Syndrome. The older the woman turns, while conceiving, the greater is the risk factor for the syndrome. For a woman who conceives after 40, there is 1 percent of the child getting Down Syndrome, though this risk I just 1 in 1000 when a woman is in between 20 and 30 years of age.
Causes of Down Syndrome
As it is a genetic disorder, Down syndrome is caused by the presence of an additional chromosome 21. Hence the disorder is also called Trisomy 21.
Every child gets 23 pairs of chromosomes, one from its mother and one from its father. When a child inherits an extra chromosome then it results in the disorder. In Down syndrome, a child more often than not inherits two copies of chromosome 21 from the mother and one chromosome 21 from the father to get a sum total of three copies of chromosomes 21.
Even though almost 94% of the patients with Down syndrome inherit a full additional chromosome, this may not be the case for other patients. This results in translocation or mosaic Down syndrome. In translocation, which happens in approximately 3% to 5% of the cases, some extra chromosome 21 genes are attached to another chromosome (usually chromosome 14). In mosaic Down syndrome, which is even rarer, the patients inherit extra genes from chromosome 21, albeit not in every cell of the body.
It is still unknown how the extra genes lead to the disorder, but scientists believe that the presence of an increased number of specific genes alters the interaction between these and other genes. This change results in the cognitive impairment and developmental delays associated with the disorder. Currently, scientists are making progress in understanding the functions of individual genes.
Down Syndrome Diagnosis
Down syndrome can be diagnosed in the prenatal stage or after birth. The screening tests before birth carry a small risk of miscarriage. Also, the tests cannot confirm with certainty the presence of Down syndrome.
There are several prenatal tests that can be conducted to check for Down syndrome. They are alpha-fetoprotein (AFP), the nuchal translucency test, Amniocentesis, Chorionic villus sampling (CVS), percutaneous umbilical blood sampling (PUB) and other ultrasound screening tests.
If Down syndrome is suspected after the birth of a child, a diagnosis can be made via chromosome analysis.
Characteristic features and symptoms of Down syndrome
Almost all patients with Down syndrome whether they are mild or profound in severity bare a few unique characteristics. They are:
• Facial features include small ears, a flat face and nose, a small mouth which is sometimes accompanied with an oversized tongue, a short thick neck, eyes that slant upwards with small skin folds at the inner corner.
• Most patients with Down syndrome have Poor muscle tone and loose ligaments.
• The palm has a single crease, whereas the hands are short and wide with little fingers.
• The colored part of the eye, i.e., the iris may have white spots.
• Growth and development is generally delayed and the average height and developmental benchmarks are often not achieved.
Cognitive impairment is the most common condition associated with Down syndrome. Cognitive development is usually delayed, and all patients with Down syndrome have mild to severe learning difficulties that last throughout their lives.
The average brain size of an individual with Down syndrome is small. Scientists have found alterations in the structure and function of some areas of brain like the hippocampus and cerebellum. The hippocampus which is responsible for learning and memory is seen to be particularly affected.
There are several other conditions that are associated with Down syndrome such as Congenital heart defects, Gastrointestinal conditions, certain types of Cancer, loss of hearing with recurrent ear infections, cervical spine instability, impairment of the visual senses, sleep apnea, obesity, constipation, infantile spasms, seizures, dementia, and early-onset Alzheimer’s disease. In addition, patients with Down syndrome may have simultaneous psychiatric or behavior conditions, such as autism spectrum disorders, attention deficit hyperactivity disorder (ADHD), depression, stereotypical motor disorders, and obsessive compulsive disorder (OCD).
Prognosis and Treatment for Down Syndrome.
Even though there is no known cure for Down syndrome, the advances in medicine and technology have dramatically increased the life expectancy of persons with Down syndrome over the past few decades. The improvement in medical care and social inclusion has enabled a physically healthy individual with Down syndrome to live an average life of 55 years and more.
Due to the limited knowledge that we have about genes and genetic disorders, the treatment for Down syndrome focuses primarily on physiological and psychological therapies. For physical ailments like heart defects, gastrointestinal issues, etc. that accompanies Down syndrome corrective surgery is required.
Children with Down syndrome should be included in the society and they should be given a stimulating environment that encourages their development and education. There are several programs and therapies like occupational and speech therapies that cater to the special needs of individuals with Down syndrome.
Adults with Down syndrome age faster than average and hence they are more prone to physical ailments like memory loss, dementia, etc. It is difficult to determine dementia or other cognitive disorders in adults as they are already cognitively impaired. Hence, it is essential for caregivers and doctors to be aware of the patients needs and teach them the skills that are necessary for independence.
Down Syndrome Pictures