A defect of the 21 st chromosome By: Nur Ajeerah Esah Binti Zainuddin Dietetic 3

Top: Normal set of Chromosomes. Bottom: Down Syndrome Chromosomes Down Syndrome, also known as Trisonomy 21, is a disorder that occurs when an extra chromosome is present on the 21 st chromosome. This takes place when, during meiosis, an egg with 22 chromosomes and a cell with 24 chromosomes are made. If the egg containing 24 chromosomes combines with a sperm containing 23 chromosomes, the new cell will have 47 chromosomes. If the extra chromosome is in the 21 st chromosome, then Down Syndrome has occurred.

Clinical picture: Down syndrome symptoms vary from person to person and can range from mild to severe. However, children with Down syndrome have a widely recognized appearance. 1-Delayed mental and social development:  Social smile,Mother recognition, speech delay.  Most individuals with Down syndrome have intellectual disability in the mild (IQ 50–70) to moderate (IQ 35–50) range.  Impulsive behavior  Poor judgment  Short attention span  Slow learning N.B Children and adults with DS are at increased risk for developing epilepsy and also Alzheimer's disease. 2-Delayed motor development:  Head support, sitting, crawling, walking, Fine motor skills are delayed.  Some children will begin walking at around 2 years of age, while others will not walk until age four.  the development of gross motor skills affection is quite variable.

3-characteristic dysmorphic features: Head & neck  Skull: Brachycephaly, delayed closure of AF, microcephaly Separated joints between the bones of the skull (sutures)  Hair: silky  Eye: Upward slanting palpebral fissure Medial epicathal fold speckled iris(brushfield iris)  Nose: Depressed nasal bridge Flattened nose  Ears: Small ears Malformed, over folded helix Underdeveloped ear lobule

 Mouth Small mouth Small oral cavity Protruded & fissured Tongue  Neck short& broad Excess skin at the nape of the neck Hands, feet &abdomen  Hands short & broad hands clinodactyly (incurved little finger) simian crease (single transverse palmer crease)  Feet short & broad feet wide gap between 1st & 2 nd toes (sandal gap)  Abdomen distention & hernia

The characteristics of a person with Down Syndrome are Small mouth Small ears Flattened nose Upward slanting eyes White spots on iris Wide short hands with short fingers Single crease in palm of hand Excessive skin at nape of neck Decreased muscle tone Separated joints between bones in the skull

 Sleep apnea  Hearing loss  Eye problems  Heart problems  Frequent ear infections  Gastrointestinal blockage  Increased risk for other infections  Weakness of back bones at top neck  Compression injury of the spinal cord

Most people who have Down Syndrome have heart problems which can lead to an early death. Those with Down Syndrome also have an increased risk of leukemia and dementia. They also have different levels of mental retardation, which is different from person to person.

There isn’t any treatment available to cure Down Syndrome. However, those with Down Syndrome need to be screened regularly for eye problems, hearing loss, and thyroid disease. Physical and speech therapy is also needed to improve language skills and teach movement. Surgery may be needed to correct heart defects and gastrointestinal blockage.

 When breast-feeding, the baby should be well supported and fully awake. The baby may have some leakage because of poor tongue control. However, many infants with Down syndrome can successfully breast-feed.  Special education and training is offered in most communities for children with delays in mental development.  Speech therapy may help improve language skills

 Physical therapy may teach movement skills.  Special educators are also often needed  Obesity can become a problem for older children and adults. Getting plenty of activity and avoiding high-calorie foods are important.  Behavioral training can help people with Down syndrome and their families deal with the anger, and compulsive behavior that often occur. At the same time, it is important to encourage independence.

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