Down syndrome is the most common chromosome abnormalities in humans. Almost 1 in 1000 births is affected by this syndrome.
The parents of the child presenting with Down’s syndrome are normal. The trisomy occurs in the chromosome of the child. In reproduction, both the parents donate one set of chromosome to their offspring. When the baby’s body cells develop, each of these cells should receive 23 pairs of the chromosome, one pair from each parent. However, in case of down’s syndrome, one of the chromosome fails to separate properly in one of the parent. Hence the child ends up having an extra copy of the chromosome number 21. This extra chromosome is responsible for Down’s syndrome’s symptoms.
The Baby suffering from down’s syndrome may suffer from following symptoms:
They have slanted eyes, flat nasal bridge, decreased muscle tone, large tongue, short neck, increased thickness of the skin at the back of the neck, stunted growth, umbilical hernia, excessive flexibility of the joints, short fingers. The Down’s babies have peculiar physical features.
The most common presentation in Down’s syndrome is that the babies have mild to moderate degree of mental retardation. They might stutter, have irregular speech, autism, depression, anxiety and seizure attacks. These children have Intelligence quotient as:
- Mild: 50-70
- Moderate: 35-50
- Severe: 20-35
The Down’s syndrome babies have birth defects in the heart. Almost 40% of the babies have a septal defect in their ventricles. They might also have problems in their valves of the heart.
Children suffering from Down’s syndrome have visual and auditory problems. Almost 80% of the children suffer from vision problems. Many of them have squint, cataracts, and may require glasses early in their childhood. Hearing problems are also fairly common. The children may have repetitive ear infections and it may result in loss of hearing at an early age. This also hampers their ability in developing proper language and speech.
They might suffer from hypothyroidism. They might also suffer from type 1 Diabetes. The chances of blood cancer and cancer of the testicles is more in the Down’s babies. The children may also have imperforate anus at birth and may suffer from celiac disease. They also have very poor dentition. There is increased risk of cleft palate and cleft lips deformity. the babies suffering from Down’s have reduced fertility in their adult lives.
Following are the main risk factors for having an offspring suffering from Down’s Syndrome:
Advancing maternal age:
as the age of the mother increases, the chances of having a Down’s baby increase. The age versus chance of having a Down’s baby are as follows:
|35 years||1 in 350|
|40 years||1 in 100|
|45 years||1 in 40|
As now-a-days, the women are conceiving later than before, the incidence of having Down’s baby has increased. Recent research suggests that advancing father’s age might also a be risk factor in resulting in a Down’s child.
One child with down’s syndrome:
If a couple already has one child suffering from Down’s syndrome. There is a possibility that a following pregnancy may also result in a Down’s baby.
Carrier of the genetic translocation related to Down’s syndrome:
Both the parent can pass the defective translocation to their children resulting in Down’s baby.
These are the symptom and risk factors of the Down’ syndrome.