Down syndrome disorder
Down syndrome is one of the most common chromosomal abnormalities. A few of the common physical traits of Down syndrome are-
- low muscle tone
- small stature
- an upward slant to the eyes and
- a single deep crease across the center of the palm.
Every child with Down syndrome is unique and and may possess these characteristics to different degrees.
Children with Down syndrome are at a high risk for certain medical conditions such as congenital heart defects, respiratory and hearing problems, childhood leukemia and thyroid conditions. Since most of these conditions can be treated, most people with DS lead healthy lives.
Life expectancy for people with Down syndrome has increased dramatically in recent decades – from 25 in 1983 to 60 today.
Other characteristics include cognitive delays, but the effect is usually mild to moderate, speech and language delays and deviances, and delayed motor milestones.
Children with Down syndrome learn to sit, walk, talk, play and do most other activities, only somewhat later than their peers without Down syndrome.
People with Down syndrome attend school, work and contribute to society in many delightful ways. The children with DS should be provided with quality educational programs, a stimulating home environment, good health care and positive support from family, friends and communities.
Features Down syndrome
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Hearing skills –
Around 2/3rd of all children with Down Syndrome have either conductive hearing loss or sensorineural hearing loss or both. Hearing loss can be in one or in both ears and ranges from mild to severe degree. Otitis media is quite commonly seen as these children have narrow auditory canals. Otitis media is seen in around 93 % of all children with Down syndrome. Around 83 % of these require ventilation ( typmpanotomy tubes) as a treatment option.
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Oral Motor Skills –
Children with Down Syndrome have small oral cavities, large tongues and narrow high arched palates. Also poorly developed facial muscles and differences in nerve innervation in the face have also been proven by research. All these features result in slow sluggish speech production and misarticulations. Also the articulators in the oral cavities of such children lack the quick motor coordination required for eloquent speech. Symptoms of childhood apraxia of speech have also been reported by some researchers.
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Cognitive Skills –
80 % of children with Down Syndrome have moderate intellectual disabilities, some have average IQ while a few others have severe disabilities. Children with Down syndrome have good visuo spatial and visual perception skills, though their visual long term memories are poor. These children and adolescents have impaired phonological skills, poor receptive language, short mean length of utterance and poor reading skills.
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Social Skills –
Children with Down syndrome are found to be socially very active, engaging, friendly and amiable. Social skills and daily living skills are strengths of majority of children with DS. Some of these children have poor social skills just like children on the autism spectrum. ( around 5% – 7%)
Causes of Down syndrome
There are 23 pairs of chromosomes that make up our genetic structure. Due to a process called as non-disjunction, which is an error in cell division, the embryo gets an extra copy of chromosome 21, instead of two. This is called as trisomy of chromosome 21. As the embryo develops, this genetic make-up is copied into every other cell of the body. 95 % of Down syndrome cases are due to Trisomy of chromosome 21.
The other two types of processes that result in this disorder are mosaicism and translocation. Mosaic Down syndrome occurs when non disjunction of chromosome 21 takes place in one but not all of the initial cells which are formed after fertilization. This causes some of the cells in the body to have regular 46 chromosomes ( 23 pairs) and some have 47 chromosomes. Those with 47 chromosomes, have an extra 21. Mosaicism accounts for 1 % of all children with Down Syndrome. This type has very few characteristics of typical DS.
In Translocation, another full or partial copy of chromosome 21 goes and attaches to chromosome 14. While the total number of chromosomes is still 46, the extra 21 bit causes features of DS. This accounts for around 4 % of all DS.
The cause of non-disjunction is still under research. Although it is found that it tends to happen more frequently in women above the age 35 years. DS is not caused by environmental factors or by parents activities before or during pregnancy. The chance of a woman to give birth to another child with Down Syndrome is 1 in 100 and increases after the age of 40 years.
Intervention
Early intervention should be a target for children with Down syndrome. Areas of focus should be parent counselling, pre linguistic skills such as eye contact, concentration and attention, joint attention, receptive and expressive language skills, cognitive and social skills.
Down Syndrome federation of India was established in 1984. It runs in Chennai and offers day care services to individuals with special needs, specifically Down syndrome. The various services provided by them includes counselling families, training children to overcome their weaknesses by providing speech therapy, physiotherapy and spreading awareness about DS.
Down syndrome federation of India bears the unique distinction of being the only centre of its kind in South India. And not just this, a lot of research programs, specialized out patient services, and early intervention programs are also conducted and co-ordinated here. Down syndrome federation of India goes with a vision and a mission.