Down’s SyndromeDown’s Syndrome

By Bailey Mulford andBy Bailey Mulford and

Rachel LanaghenRachel Lanaghen

OVERVIEWOVERVIEW

Down’s syndrome, Down’s syndrome, named after Dr. John named after Dr. John Langdon Down, is a Langdon Down, is a chromosomal chromosomal disorder. It is caused disorder. It is caused due to trisomy, the due to trisomy, the presence of an extra presence of an extra copy, of the 21copy, of the 21stst chromosome. chromosome.

PHYSICAL SYMPTOMSPHYSICAL SYMPTOMS

Typically have a very round faceTypically have a very round face““Almond-shaped” eyesAlmond-shaped” eyesBrushfield spots (white spots on Brushfield spots (white spots on the iris)the iris)Flat bridge of the noseFlat bridge of the noseProtruding tongue due to a small Protruding tongue due to a small oral cavity and enlarged tongue)oral cavity and enlarged tongue)Shorter neckShorter neckCongenital heart defectsCongenital heart defectsLarge space between the big toe Large space between the big toe and second toeand second toeMuscle hypotonia (poor muscle Muscle hypotonia (poor muscle tone)tone)Most exhibit mild to moderate Most exhibit mild to moderate mental retardationmental retardation

INHERITANCEINHERITANCE

Down’s is inherited one of three ways…Down’s is inherited one of three ways…1.1. Non-disjunction (95%) – during meiosis, a Non-disjunction (95%) – during meiosis, a

gamete ends up with 24 chromosomes rather gamete ends up with 24 chromosomes rather than the usual 23than the usual 23

2.2. Translocation (3-4%) – where one of the Translocation (3-4%) – where one of the parents has chromosome 21 attached to parents has chromosome 21 attached to another chromosome, usually chromosome 14another chromosome, usually chromosome 14

3.3. Mitotic Errors (<3%) – in early development of Mitotic Errors (<3%) – in early development of the fetus, the chromosome 21 pair fails to the fetus, the chromosome 21 pair fails to separate in anaphaseseparate in anaphase

STATISTICSSTATISTICS

Down’s Syndrome is Down’s Syndrome is estimated to be anywhere estimated to be anywhere from 1 in 800 to 1 in 1000from 1 in 800 to 1 in 1000As of 2006, the estimate As of 2006, the estimate was 1 in 733 live birthswas 1 in 733 live birthsMaternal age has a Maternal age has a strong influence on if the strong influence on if the baby has a third copy of baby has a third copy of chromosome 21. As chromosome 21. As shown in the graph to the shown in the graph to the right, as the age of the right, as the age of the mother increases, the mother increases, the instances with Down’s instances with Down’s increases accordingly.increases accordingly.

PROGNOSIS AND TREATMENTPROGNOSIS AND TREATMENT

Down’s Syndrome can be detected through a number of prenatal Down’s Syndrome can be detected through a number of prenatal screening techniques including…screening techniques including…Amniocentesis- sample of amniotic fluidAmniocentesis- sample of amniotic fluidChronice villus sampling (CVS)Chronice villus sampling (CVS)Percutaneous umbilical blood sampling (PUBS)Percutaneous umbilical blood sampling (PUBS)Triple screen- measures protein and hormone levelsTriple screen- measures protein and hormone levelsQuad screen- measures protein and hormone levelsQuad screen- measures protein and hormone levelsAFP/free beta screen- measures protein levelsAFP/free beta screen- measures protein levelsPAPPA screen- uses ultrasound that measures protein levelsPAPPA screen- uses ultrasound that measures protein levels

These tests are 90-95% accurate with 2-5% false positives.These tests are 90-95% accurate with 2-5% false positives.

At present, there are no cures or treatment for Down’s Syndrome. At present, there are no cures or treatment for Down’s Syndrome. However, many of the symptoms such as congenital heart failure However, many of the symptoms such as congenital heart failure may be treated with various medications.may be treated with various medications.

LIFE EXPECTANCYLIFE EXPECTANCY

Individuals with Down’s Syndrome have a Individuals with Down’s Syndrome have a slightly higher morbidity rate due to impaired slightly higher morbidity rate due to impaired immune responses, increase in congenital heart immune responses, increase in congenital heart disease, and airway obstructions. The disease, and airway obstructions. The estimated lifespan is 49 years, which is a estimated lifespan is 49 years, which is a dramatic increase from the 24 years of age in dramatic increase from the 24 years of age in 1980.1980.

75% die in embryonic or fetal life75% die in embryonic or fetal life15% die within the first year after their birth15% die within the first year after their birth50% live past 50 years of age50% live past 50 years of age

LIVING WITH DOWN’S LIVING WITH DOWN’S SYNDROMESYNDROME

From the early 20From the early 20thth century through the 1960s century through the 1960s many people with down syndrome were put many people with down syndrome were put into institutions, largely excluded from the rest into institutions, largely excluded from the rest of society. of society.

Now that scientists and doctors better Now that scientists and doctors better understand this disorder a more humane understand this disorder a more humane policy of policy of inclusioninclusion has been initiated. has been initiated.

InclusionInclusion

Inclusion is a strategy that works at meeting the needs Inclusion is a strategy that works at meeting the needs of people with down syndrome as much as possible in of people with down syndrome as much as possible in public education and developmental institutions. There public education and developmental institutions. There are many academic and social benefits for both are many academic and social benefits for both students with the disorder and students without it when students with the disorder and students without it when they are given the opportunity to learn and grow they are given the opportunity to learn and grow together.together.

1.1. New FriendshipsNew Friendships2.2. Non-disabled students are more appreciative of Non-disabled students are more appreciative of

differences differences 3.3. Students with disabilities are more motivated when Students with disabilities are more motivated when

they are pushed to their potential like any other personthey are pushed to their potential like any other person

LIVING WITH DOWN SYNDROMELIVING WITH DOWN SYNDROMEToday…Today…

Most children with down syndrome go to public school and Most children with down syndrome go to public school and participate in many of the same activities as non-disabled participate in many of the same activities as non-disabled students (although some do perform better in specialized students (although some do perform better in specialized programs)programs)Many go to collegeMany go to collegeMany live in semi-independent housing and hold jobsMany live in semi-independent housing and hold jobsThe National Down Syndrome Society is trying to expand post The National Down Syndrome Society is trying to expand post secondary opportunities by developing a model school/program secondary opportunities by developing a model school/program especially fitted for people with down syndrome.especially fitted for people with down syndrome.Their fertility is significantly decreased (only 3 recorded fathers in Their fertility is significantly decreased (only 3 recorded fathers in history) and there is no evidence to support that this a hereditary history) and there is no evidence to support that this a hereditary disorder.disorder.Most people with this disorder live happy, rewarding lives. Most people with this disorder live happy, rewarding lives. Gradually mainstream society is beginning to understand the Gradually mainstream society is beginning to understand the unique and contributions and talents they have. unique and contributions and talents they have.

ResourcesResources

Local support groups and instructional programs for new Local support groups and instructional programs for new parents and relatives can be found through these parents and relatives can be found through these national organizations:national organizations:

National Down Syndrome Congress National Down Syndrome Congress www.ndsscenter.orgwww.ndsscenter.org National Association for Down Syndrome National Association for Down Syndrome www.nads.orgwww.nads.orgNational Down Syndrome Society National Down Syndrome Society www.ndss.orgwww.ndss.orgBand of Angels Foundation www.bandofangels.com Band of Angels Foundation www.bandofangels.com

WORKS CITEDWORKS CITED

““Down’s Syndrome”, Wikipedia, Down’s Syndrome”, Wikipedia, http://en.wikipedia.org/wiki/Down%27s_syhttp://en.wikipedia.org/wiki/Down%27s_sydromedrome

““Down’s Syndrome”, Down’s Syndrome”, BioZoneBioZone, pg.203, pg.203

““Down Syndrome” eMedicine Down Syndrome” eMedicine http://emedicine.com/ped/topic615.htmhttp://emedicine.com/ped/topic615.htm