Introduction to Down Syndrome
Down syndrome is a genetic disorder where someone is born with an extra copy of chromosome 21.
What is Down Syndrome?
Down syndrome is a genetic disorder where someone is born with an extra copy of chromosome 21. There is no cure for Down syndrome; it will affect someone throughout his or her life. It is the most common chromosome problem in humans affecting 1 in 1000 babies born in the UK.
What causes Down Syndrome?
An extra copy of chromosome 21 is the cause of Down syndrome. This is called trisomy 21. Full trisomy 21 is the most common form of Down syndrome. Mosaic Down syndrome is a rare cause. It is when only some of the cells in the body have trisomy 21. Translocation Down syndrome is when one of the parents carries a part of their chromosome 21 attached to chromosome 14. The extra chromosome 21 can be inherited by their offspring.
Pregnant women have the option to look at your risk of having a baby with Down syndrome. This usually involves a blood test and an ultrasound scan to measure the thickness of fluid that collects around the babies’ neck. Down syndrome babies collect more fluid here than usual. If the risk is deemed to be high there are two prenatal diagnostic tests that can be done: amniocentesis and chorionic villus sampling. These tests are invasive and do carry the small risk of miscarriage.
Postnatal diagnosis can be confirmed by doing a blood test to look at the babies’ genetics.
What are the symptoms of Down Syndrome?
Facial and other physical features are typical in people with Down syndrome. These include: an oval shaped face, a small mouth, a tongue that protrudes, a smaller nose with a flat and low bridge, small and low set ears and an extra skin fold on the upper eyelid. Other physical features include: a single palm crease, loose joints, a larger space between the first and second toe, muscles that lack tone and short fingers and a little finger that curves inwards.
Down syndrome sufferers also have some degree of physical and mental development. Such as learning difficulties, delayed speech and delayed motor development. Sufferers will also have a lower than average IQ.
Approximately half of sufferers will have a congenital heart defect. The most common is an atrioventricular septal defect, which is when there is a hole in the muscle that separates the top of the heart from the bottom. This can be corrected by surgery if detected.
Other problems include: vision problems, ear infections, leukaemia, frequent infections, thyroid problems, diabetes, premature aging and reduced fertility.
How is Down Syndrome treated?
There is no treatment that can cure Down syndrome. Monitoring for complications is important. Programmes are available to develop speech and language and help with the learning and development of a child. A number of doctors will involved in the care of Down syndrome sufferers including a: general practitioner, paediatrician, cardiologist, ophthalmologist, physiotherapist and a speech and language therapist.