down syndrome

C I I T

Sameen Noushad

2014

GENETICS ASSIGNMENTDOWN SYNDROME

DOWN SYNDROME April 20, 2014

| 1

Table of ContentsINTRODUCTION.............................................................................................................................................2

GENETICS OF DOWN SYNDROME: ................................................................................................................ 3

SYMPTOMS ...................................................................................................................................................4

Physical .....................................................................................................................................................4

Neurological ..............................................................................................................................................5

Senses .......................................................................................................................................................5

Heart .........................................................................................................................................................6

Cancer .......................................................................................................................................................6

Fertility ......................................................................................................................................................6

Prognosis for People with Down syndrome..................................................................................................7

Life of Adults: ............................................................................................................................................7

Life of Children:.........................................................................................................................................7

Management for People with Down syndrome ...........................................................................................8

Health Screening:...................................................................................................................................... 8

Cognitive development:............................................................................................................................8

Drugs and Supplements: ........................................................................................................................... 9

References: .................................................................................................................................................10

INTRODUCTION

Down syndrome is a chromosomal disorder caused by a which is an extra 21st chromosome. The condition leads to impairments in both capability and physical developmentscreenings and tests, Down syndrome can be detected before and after known to affect the likelihood of having a baby with Down syndrome is maternal age. That is, less than one in 1,000 pregnancies for mothers less than 30 years of age results in a baby with Down syndrome. For mommies who are 44 years of age, about 1 in 35 pregnancies results in a baby with Down syndrome. Because younger children with the disorder are born to younger women.(http://www.medicalnewstoday.com/articles/145554.php)

(Agathokleous et.al ,2013)(Verweij, EJ et.al, 2012)

Testing of the mother's blood for fetal DNA is studied and is

helpful in the first trimester.Accuracy goes as high as 98.6% in the first trimester of pregnancy. Invasive techniques

for confirmation are(amniocentesis, CVS) needed to confirm the screening result.

DOWN SYNDROME

DOWN SYNDROME

Down syndrome is a chromosomal disorder caused by a fault in cell division; the outcome of an extra 21st chromosome. The condition leads to impairments in both

development ranging from mild to moderate levels. Afterscreenings and tests, Down syndrome can be detected before and after birth. The only factor

of having a baby with Down syndrome is maternal age. That is, regnancies for mothers less than 30 years of age results in a baby with

who are 44 years of age, about 1 in 35 pregnancies results in a baby with Down syndrome. Because younger ladies generally have more children, 75

are born to younger women.(http://www.medicalnewstoday.com/articles/145554.php)

Testing of the mother's blood for fetal DNA is studied and is

helpful in the first trimester.Accuracy goes as high as 98.6% in the first trimester of pregnancy. Invasive techniques

for confirmation are(amniocentesis, CVS) needed to confirm the screening result.

Ultrasound imaging can be used aswell. Evidence that indicate

the syndrome when seen at 14 to 24 weeks of pregnancy

include: a small or no nasal bone, large ventricles, nuchal

fold thickness, and an abnormal right subclavian artery and so

on.

DOWN SYNDROME


| 2

e outcome of an extra 21st chromosome. The condition leads to impairments in both mental

levels. After series of . The only factor

of having a baby with Down syndrome is maternal age. That is, regnancies for mothers less than 30 years of age results in a baby with

who are 44 years of age, about 1 in 35 pregnancies results in a generally have more children, 75 - 80% of

Ultrasound imaging can be used aswell. Evidence that indicate

the syndrome when seen at 14 to 24 weeks of pregnancy

include: a small or no nasal bone, large ventricles, nuchal

fold thickness, and an abnormal right subclavian artery and so

DOWN SYNDROME


| GENETICS OF DOWN SYNDROME: 3

GENETICS OF DOWN SYNDROME:

Down syndrome results when one of three types of abnormal cell division involving chromosome 21 occurs. All three cell division abnormalities result in extra genetic material from chromosome 21, which is responsible for the characteristic features and developmental problems of Down syndrome. The three genetic variations that

can cause Down syndrome include: (http://www.mayoclinic.org/diseases-conditions/down-syndrome/basics/causes/con-20020948)

Tris

omy

21 . More than 90 percent of the time, Down syndrome is caused by trisomy 21. A child with trisomy 21 has three copies of chromosome 21 —instead of the usual two copies — in all of his or her cells. This form of Down syndrome is caused by abnormal cell division during the development of the sperm cell or the egg cell.

Mos

aic

Dow

n Sy

ndro

me In this rare form of Down

syndrome, children have some cells with an extra copy of chromosome 21. This mosaic of normal and abnormal cells is caused by abnormal cell division after fertilization.

Tran

sloc

atio

n D

own

Synd

rom

e Down syndrome can also occur when part of chromosome 21 becomes attached (translocated) onto another chromosome, before or at conception. Children with translocation Down syndrome have the usual two copies of chromosome 21, but they also have additional material from chromosome 21 attached to the translocated chromosome. This form of Down syndrome is uncommon.

SYMPTOMS

PhysicalThose with Down syndrome nearly always (http://www.webmd.com/children/understanding

Small chin Slanted Eyes

Single palmar crease

Protruding tongue

Space in toe and fingers Short fingers

DOWN SYNDROME

| SYMPTOMS

Those with Down syndrome nearly always have physical and intellectual disabilities:(http://www.webmd.com/children/understanding-down-syndrome-symptoms)

Slanted Eyes Poor muscle tone

Protruding tongue Flat face

Short fingers


SYMPTOMS 4

have physical and intellectual disabilities:

Flat nasal bridge

Short neck

Neurological

Senses

Down’s syndrome is associated closely to hearing and vision disabilities. Around 38having the syndrome suffer from it.

Hearing problems are found in 502012.)

STRABISMUS: Around 20 and 50% have it, in which the two eyes do not move together. (Weijerman,

Cataracts : (cloudiness of the lens of the eye) can be there from birth and accounts to 15% of individuals. ("Down Syndrome and Other Abnormalities of Chromosome Number". Nelson textbook of pediatrics. (19th ed. ed.). Philadelphia: Saunders. 2011.)

Keratoconus: (a thin, conepressure) are also more common. (Weijerman

Brushfield spots (small white or grayish/brown spots on the outer part of the iris) are prevalant in 38 to 85% of individuals. (Weijerman,

DOWN SYNDROME

| SYMPTOMS

It is common that individuals with Down syndrome have mild (IQ: 50–70) or moderate (IQ: 35–50) or severe (IQ: 20–35).et.al, 2010)

Children and adults with Down syndrome are at increased risk of epileptic seizuresspasms and Alzheimer’s. (M. William Schwartzet.al, 2012)

Down’s syndrome is associated closely to hearing and vision disabilities. Around 38having the syndrome suffer from it. (Weijerman, et.al, 2010)

Hearing problems are found in 50–90% of children with Down syndrome. (Rodman

STRABISMUS: Around 20 and 50% have it, in which the two eyes do not move together. (Weijerman,et.al, 2010)

Cataracts : (cloudiness of the lens of the eye) can be there from birth and accounts to 15% of individuals. ("Down Syndrome and Other Abnormalities of Chromosome Number". Nelson textbook of pediatrics. (19th ed. ed.). Philadelphia: Saunders. 2011.)

Keratoconus: (a thin, cone-shaped corneas) and glaucoma (increased eye pressure) are also more common. (Weijermanet.al, 2010.)

Brushfield spots (small white or grayish/brown spots on the outer part of the iris) are prevalant in 38 to 85% of individuals. (Weijerman,


SYMPTOMS 5

individuals with Down 70) or moderate 35). (Weijerman

Children and adults with Down syndrome are at epileptic seizures , infantile

M. William Schwartz

Down’s syndrome is associated closely to hearing and vision disabilities. Around 38-80% people

(Rodman et.al,

STRABISMUS: Around 20 and 50% have it, in which the two eyes do not move

Cataracts : (cloudiness of the lens of the eye) can be there from birth and accounts to 15% of individuals. ("Down Syndrome and Other Abnormalities of Chromosome Number". Nelson textbook of pediatrics. (19th ed. ed.).

shaped corneas) and glaucoma (increased eye

Brushfield spots (small white or grayish/brown spots on the outer part of the iris) are prevalant in 38 to 85% of individuals. (Weijerman, et.al, 2010)

Heart

1. 40% of individuals with the syndrome have (2007). The consequences of chromosome imbalance : principles, mechanisms, and models. Cambridge: Cambridge University Press. pp. 255

2. Whereas 80% are known to suffer from

Fertility

Females has a low fertility rate as compared to unaffected ones, whereas males do not have a tendency to have offspring. In 2006 there have been having babies and 26 circumstancestechnologies, approximately half of the pregnancies of someone with Down syndrome will also have the syndrome. (Pradhan et.al , 2010)

Two beautiful sisters, suffering from Down Syndrome and leukemia

DOWN SYNDROME

| SYMPTOMS

40% of individuals with the syndrome have congenital heart disease. (Epstein, Charles J. (2007). The consequences of chromosome imbalance : principles, mechanisms, and models. Cambridge: Cambridge University Press. pp. 255–256.)

are known to suffer from atrioventricular septal defect or septal defect. (Malt et.al, 2013)

Cancer

The risk of cancer remains but the cancers that are more commonly associated with Down syndrome are leukemia and testicular cancer. Solid cancers are less common. (Malt et.al, 2013)

Chromosome 21 has more expression of tumor suppresser genes and this actually leads to low risk of solid cancers. Thomas-Tikhonenko, ed. (2010). Cancer genome and tumor microenvironment (Online-Ausg. ed.). New York: Springer. p. 203.)

has a low fertility rate as compared to unaffected ones, whereas males do not have a 2006 there have been 3 records of males with Down syndrome

circumstances of women having children. Without assisted reproductive , approximately half of the pregnancies of someone with Down syndrome will also

et.al , 2010)

Two beautiful sisters, suffering from Down Syndrome and leukemia


SYMPTOMS 6

(Epstein, Charles J. (2007). The consequences of chromosome imbalance : principles, mechanisms, and

or ventricular et.al, 2013)

The risk of cancer remains but the cancers that are more commonly associated with

emia and testicular cancer. Solid cancers are less

13)

Chromosome 21 has more expression of tumor suppresser genes and this actually leads to low risk of solid cancers. (Andrei

Tikhonenko, ed. (2010). Cancer genome and tumor microenvironment

Ausg. ed.). New York: Springer.

has a low fertility rate as compared to unaffected ones, whereas males do not have a of males with Down syndrome

assisted reproductive , approximately half of the pregnancies of someone with Down syndrome will also

harshness of medical problems and early times the Down syndrome patients were expected to live less than 10 years. Now, 80% of adult Down syndrome patients

(http://www.who.int/genomics/public/geneticdiseases/en/index1.html

Life of Children: Quality of life also has improved for many children with Down syndrome, but living with the condition is not without difficulties. Generally, children with Down syndrome are able to attend school. Many children with Down syndrome learn to read and write and enjoy the same activities as other kids their age, such as sports, art, and music programs.

DOWN SYNDROME

| /Prognosis for People with Down syndrome

Prognosis for People with Down syndrome

The prognosis of Down syndrome isdepending upon the possible complications like heart defects, several development of leukemia.

Although the prognosis for children who have Down syndrome depends on the

of medical problems and obstacles that develop, it has boosted over the years.the Down syndrome patients were expected to live less than 10 years. Now,

80% of adult Down syndrome patients celebrate their 50th birthday and even longer !

http://www.who.int/genomics/public/geneticdiseases/en/index1.html

Quality of life also has improved for many children with Down syndrome, but living with the condition is not without difficulties. Generally, children with Down syndrome

school. Many children with Down syndrome learn to read and write and enjoy the same activities as other kids their age, such as sports, art, and

Life of Adults:As adults, people with Down syndrome may live with their families or in community group homes, where they often are able to take care of their own needs. They may work in offices, nursing homes, hotels, restaurants, and other places of employment. People who have Down syndrome may marry and have children; however, pregnant women with the condition are at high risk for miscarriage.(http://down-syndrome.emedtv.com/downsyndrome/down-syndrome-prognosis.html


/Prognosis for People with Down syndrome 7

Prognosis for People with Down syndrome

The prognosis of Down syndrome is changingdepending upon the possible complications like heart defects, several infections and development of leukemia.

Although the prognosis for children who have Down syndrome depends on the

over the years. As in the Down syndrome patients were expected to live less than 10 years. Now, about

birthday and even longer !

http://www.who.int/genomics/public/geneticdiseases/en/index1.html)

As adults, people with Down syndrome may live with their families or in community group homes, where they often are able to take care of their own needs. They may work in offices, nursing homes, hotels, restaurants, and other

who have Down syndrome may marry and have children; however, pregnant women with the condition

syndrome.emedtv.com/down-prognosis.html)


| Management for People with Down syndrome 8

Management for People with Down syndrome

Efforts such as early childhood intervention, screening for common problems, medical treatment where indicated, a decent family atmosphere, and work related exercise can improve the development of children with Down syndrome. Schooling and proper attention can improve quality of life. Typical childhood vaccinations are recommended.(Hickey & Summar, 2012)

Health Screening:

A number of health organizations have issued commendations for screening those with Down syndrome for specific ailments. (Bull, 2011)

At birth all children must get an electrocardiogram and ultrasound of the heart. Surgical repair of heart problems may be required as early as three months of age. Heart valve problems may occur in young adults, and further ultrasound assessment may be required in young people and in early adulthood. (Hickey & Summar, 2012)

Cognitive development:

Delay in the development of cognitive capacities is a prime result of Down syndrome. In spite ofsuch cognitive delay, however, young children with Down syndrome can be empathic, friendly

and

engaging. (Wishart & Pitcairn, 2000).

Hearing aids can be useful for language learning in those with hearing lossSummar, 2012). People with Down syndrome can typically have good hand eye coordination; learning sign language may be promisingcommunication methods, such as pointing, body language, used to help with communication even though there is 2007)

trials of these treatments were poorly controlled and revealed adverse effects from these treatments. Since then, newer psychoactive drugs that are much more developed. No controlled clinical studies of these medications for Dowdemonstrated their safety and efficacy, however. Many studies of drugs to treat symptoms of dementia in Down syndrome have included only a few participants. The results of these studies have not shown flawless benefits of these drugs, eithedementia in Down syndrome have shown that these effective. (https://www.nichd.nih.gov/health/topics/down/conditioninfo/Pages/treatments.aspx#f8

DOWN SYNDROME

| Management for People with Down syndrome

for language learning in those with hearing loss (Hickey Down syndrome can typically have good hand eye coordination;

may be promising (Reilly, 2012). Other alternative methods, such as pointing, body language, items, or photographs

communication even though there is slight actual confirmation

trials of these treatments were poorly controlled and revealed adverse effects from these treatments. Since then, newer psychoactive drugs that are much more precise have been developed. No controlled clinical studies of these medications for Down syndrome have demonstrated their safety and efficacy, however. Many studies of drugs to treat symptoms of dementia in Down syndrome have included only a few participants. The results of these studies

benefits of these drugs, either. Similarly, studies of antioxidants for dementia in Down syndrome have shown that these supplements are harmless

d.nih.gov/health/topics/down/conditioninfo/Pages/treatments.aspx#f8


Management for People with Down syndrome 9

Hickey & Down syndrome can typically have good hand eye coordination;

photographs are often actual confirmation (Roberts et.al,

Drugs and Supplements:

Some people with Down syndrome take amino acid supplements or drugs that affect their brain activity. However, many of the latest clinical

trials of these treatments were poorly controlled and revealed adverse effects from these have been

n syndrome have demonstrated their safety and efficacy, however. Many studies of drugs to treat symptoms of dementia in Down syndrome have included only a few participants. The results of these studies

r. Similarly, studies of antioxidants for harmless, but not

d.nih.gov/health/topics/down/conditioninfo/Pages/treatments.aspx#f8)


| References: 10

References: 1. Weijerman, ME; de Winter, JP (Dec 2010). "Clinical practice. The care of children with

Down syndrome.". European journal of pediatrics 169 (12): 1445–52.2. Weijerman, ME; de Winter, JP (Dec 2010). "Clinical practice. The care of children with

Down syndrome.". European journal of pediatrics 169 (12): 1445–52.

3. Epstein, Charles J. (2007). The consequences of chromosome imbalance : principles, mechanisms, and models. Cambridge: Cambridge University Press. pp. 255–256.

4. Malt, EA; Dahl, RC; Haugsand, TM; Ulvestad, IH; Emilsen, NM; Hansen, B; Cardenas, YE; Skøld, RO; Thorsen, AT; Davidsen, EM (Feb 5, 2013). "Health and disease in adults with Down syndrome. Tidsskrift for den Norske laegeforening : tidsskrift for praktisk medicin, ny raekke 133 (3): 290–4"

5. Malt, EA; Dahl, RC; Haugsand, TM; Ulvestad, IH; Emilsen, NM; Hansen, B; Cardenas, YE; Skøld, RO; Thorsen, AT; Davidsen, EM (Feb 5, 2013). "Health and disease in adults with Down syndrome. Tidsskrift for den Norske laegeforening : tidsskrift for praktisk medicin, ny raekke 133 (3): 290–4"

6. (Andrei Thomas-Tikhonenko, ed. (2010). Cancer genome and tumor microenvironment (Online-Ausg. ed.). New York: Springer.

7. Pradhan, M; Dalal, A; Khan, F; Agrawal, S (2006). "Fertility in men with Down syndrome: a case report". Fertil Steril 86 (6): 1765.e1–3.

8. Weijerman, ME; de Winter, JP (Dec 2010). "Clinical practice. The care of children with Down syndrome.". European journal of pediatrics 169 (12): 1445–52.

9. "Down Syndrome and Other Abnormalities of Chromosome Number". Nelson textbook of pediatrics. (19th ed. ed.). Philadelphia: Saunders. 2011.



12. Agathokleous, M; Chaveeva, P; Poon, LC; Kosinski, P; Nicolaides, KH (Mar 2013). "Meta-analysis of second-trimester markers for trisomy 21.". Ultrasound in obstetrics & gynecology : the official. 41 (3): 247–61. )

13. Verweij, EJ; van den Oever, JM; de Boer, MA; Boon, EM; Oepkes, D (2012). "Diagnostic accuracy of noninvasive detection of fetal trisomy 21 in maternal blood: a systematic review.". Fetal diagnosis and therapy 31 (2): 81–6.)

14. Hickey,E, Summar KL, 2012 ‘Medical update for children with Down syndrome for the pediatrician and family practitoner’ Advances in Pediatrics 59 (1) : 137-57.


| References: 11

15. Bull, MJ; Committee on, Genetics (Aug 2011). "Health supervision for children with Down syndrome.". Pediatrics 128 (2): 393–406.

16. Wishart, J. G. & Pitcairn, T. K. (2000). Recognition of identity and expression in faces by children with Down syndrome. American Journal on Mental Retardation, 105(6), 466-479.

17. Reilly, C, 2012 ‘ Behavioural phenotypes and special educational needs: is aetiology important in the classroom’ Journal of Intellectual disability research 56(10) pp 46-929

18. Roberts, JE; Price, J; Malkin, C (2007). "Language and communication development in Down syndrome". Ment Retard Dev Disabil Res Rev 13 (1): 26–35.

19. http://www.webmd.com/children/understanding-down-syndrome-symptomsRetrieved on April 14, 2014 at 5.45pm

20. http://www.mayoclinic.org/diseases-conditions/down-syndrome/basics/causes/con-20020948Retrieved on April 14, 2014 at 6.30pm

21. http://www.who.int/genomics/public/geneticdiseases/en/index1.htmlRetrieved on April 15, 2014 at 5:30 pm

22. http://down-syndrome.emedtv.com/down-syndrome/down-syndrome-prognosis.htmlRetrieved on April 15, 2014 at 5:36 pm

23. https://www.nichd.nih.gov/health/topics/down/conditioninfo/Pages/treatments.aspx#f8Retrieved on April 16, 2014 at 2.25 pm

24. http://www.medicalnewstoday.com/articles/145554.phpRetrieved on April 14, 2014 at 5:45 pm

down syndrome

Documents