Down Syndrome Research Paper

Keema Robertson

Mrs.Matthews

Down's Syndrome

Down's syndrome is a genetic condition involving an extra chromosome,

this change occurs around the time of conception. A person with Down's syndrome

has forty-seven chromosomes instead of the usual forty-six. A relatively common

genetic disorder, Down's strikes 1 out of 600 babies. In 95 percent of all

cases, the disorder originates with the egg, not the sperm, and the only known

risk factor is advanced maternal age-at age 35, a woman has 1 chance in 117 of

having a baby with Down's; at 40, her odds are 1 in 34. (Graves, 1990) People

with Down's syndrome all have a certain degree of learning disability . This

means that they develop and learn more slowly than other children. However, most

children with Down's syndrome today will walk and talk, many will read and

write, go to ordinary school, and look forward to a semi-independent adult life.

(Platt and Carlson, 1992) Facts on Down Syndrome *Down syndrome is not a lethal

anomaly. One to two percent of persons born with this disorder have

uncorrectable heart defects at birth. The average life expectancy for all others

is now beyond age 55 years. *Today less than 5% of persons with Down syndrome

have severe-to-profound mental retardation. The majority are on the border of

mild-to-moderate mental retardation, and some are exhibiting normal IQ scores

today. *The average reading level for persons with Down syndrome is 3rd grade,

with many reading at 6th-12th grade levels today. *The vast majority of adults

with Down syndrome today can be expected to live semi- or totally independently

and many enter the work force with today's supported employment programs and

some are competitively employed. Some medical conditions that demand special

attention for people with Down syndrome include: *Congenital Heart Disease:

usually in the form of endocardial cushion defects, affects 40% of babies and

should be screened for by echocardiography soon after birth as it may well be

difficult to detect. * Gastrointestinal disorders: the most common congenital

abnormality of the gastrointestinal tract associated with Down syndrome is

duodenal atresia, although pyloric stenosis, Hirschsprung's disease and

tracheo-oesophageal fistulae have all been reported. * Vision: Three percent of

newborns with Down syndrome will have dense congenital cataracts which should be

removed early. Glaucoma is also common. * Congenital Hypothyroidism: This

condition is slightly more prevalent in babies with Down syndrome. It should be

detected by the routine heelprick screen performed on all babies. *Congenital

dislocation of the hips: Joint laxity and hypotonia can combine to increase the

incidence of hip dislocation, although true congenital dislocation is quite

rare. * Sensory deficits: Significant hearing impairments occur in the majority

of children with Down syndrome. Annual audiometry and specialist consultation is

recommended. * Atlantoaxial instability: Up to 15% of children with Down

syndrome will have evidence of instability of the atlantoaxial joint but in only

a handful of cases will this instability result in an impingement on the spinal

cord with resultant neurological signs. * Physical growth: Physical development

is invariably delayed in children with Down syndrome. A tendency towards obesity

requires special attention to healthy diet and exercise habits in this group. *

Dental care: The teeth of children with Down syndrome tend to be small,

irregularly spaced and misshapen. Early and frequent dental care is required to

ensure adequate dentition for adult life. * Psychiatric disorders: Psychiatric

illnesses occur in people with Down syndrome with much the same frequency as in

the rest of the population. *Dementia: Much recent attention has been focused on

the association between Down syndrome and Alzheimer's disease. There appears to

be a gene-dose effect where having an extra chromosome 21 gives an individual a

higher chance of developing Alzheimer's disease. (Newton, 1992) A significant

amount of research has been conducted on Down syndrome, in particular many

methods to detect Down syndrome in fetuses have been developed. This is a

controversial issue for researchers and for families who have Down syndrome

children and adults. The following is a discussion of some of the detection

methods for Down syndrome, and the facilities in which they were developed.

Jones Institute Scientists at Norfolk's Jones Institute for Reproductive

Medicine say they have overcome most technical hurdles to screening embryos for

Down syndrome and many other chromosomal defects before the embryos are

implanted

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