Down Syndrome: Also called as Trisomy 21 Down syndrome is one of the common chromosomal abnormality.Down syndrome is very dependent on the age of the mother. There is high risk when the age of the mother is over 35 years.
In the early part of the 20th century, Dr Langdon Down specifically described all the features associated with the condition.
Down syndrome is caused by a chromosomal abnormality and there are two distinct ways in which the abnormality can arise.
- The commonest pattern occurs when an extra chromosome is added in the 21 position. Hence the name Trisomy 21. So the total chromosome count, under these conditions, will be 47 chromosomes instead of the usual 46.
The risk of this occurring is greater with advancing maternal age.
- But in about 5% of cases, the extra chromosome is added on to another chromosome. Under these circumstances, the total chromosome count in the affected baby will be the normal 46. But there will be one ‘compound’ chromosome in this number
Diagnosis of Down syndrome can be made at birth by the very specific physical characteristics shown by these babies.
- Facial features include an upward slant to the eyes with marked epicanthic folds.
- A small head with a short neck is a typical feature.
- The tongue is large and has distinctive deep furrows on the surface.
- The majority of Down syndrome children have white flecks on the iris- Brushfield’s spots. These spots cause no problems with vision.
- Limbs are relatively short, making final height on the low side of average. Bodily proportions are normal (cf achondroplasia).
- Fingers are short and stubby and have a characteristically intuming little finger in many babies. There is usually a single palmar crease.
- Feet have a specific characteristic in that the great toe is widely separated from the other toes.
- Muscle tone is always poor, so that Down syndrome babies are usually ‘floppy’. Subsequent physical development is slower than normal and walking occurs relatively late
These are the specific characteristics by which a Down syndrome baby can be recognized at birth. Confirmation will need to be done by chromosomal analysis.
DISEASES FREQUENTLY ASSOCIATED TO DOWN SYNDROME:
There are some of the diseases which are frequently associated with people with Down Syndrome.
- Congenital heart disease :The most common anomalies are atrial septal defects, ventricular septal defects and/or patent ductus arteriosus.
- Upper respiratory tract infections: These are common throughout infancy and childhood. This is in part due to the narrowing of the air passages, and also due to an impaired immune system.
- Thyroid disease: Both hypo- and hyper-thyroidism occurs in about 20% of Down syndrome children. The former is the most common.
- Acute lymphatic leukaemia: It has a higher incidence in Down children, and is responsible for around 5% of deaths in early childhood.
How can we help them with these problems to make their life easier and happier? Here are a few implications below which can help to maximize their abilities.
- Regarding eye abnormalities: If Squints present then should be assessed and correction undertaken, by orthoptic or surgical means, if amblyopia is to be avoided.
- Treatment of Respiratory tract infections: Bronchitis. following on from upper respiratory tract infections, is common in Down’s syndrome children, also needing adequate treatment.
- Care for Deafness: It is caused by frequent middle ear disease. needs assessment and treatment.Myringotomy, to remove sticky secretions from the middle ear. is necessary in the early stages. Most of the Down syndrome children will need hearing aids later in life
- Care of Thyroid diseases: Thyroid disease should always be in concern in case of Down Syndrome. Any excessive slowing of activity with weight gain, specific hair loss and a hoarsening of the voice, should alert carers to the possibility of hypothyroidism can be treated with Thyroxine.
- Weight control: Excess weight is often gained due to the relative immobility of these children. Dietetic advice is valuable.
If the first year of life is survived, Down syndrome children have an average life expectancy of around 40 to 50 years, although ages of over 60 have been attained. Mortality during the first year of life is usually due to congenital heart disease and/or respiratory tract infections. Malignancies, particularly leukaemia, account for deaths later in childhood. Down children should live as part of a normal family if at all possible. Their affectionate, happy personality flowers within the love and security of the family unit.
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