Down Syndrome Quiz | Health and Human Biology

Quiz Answer Key and Fun Facts

1. Down syndrome was named for John Langdon Down who, in 1866, described the syndrome in a paper entitled 'Observations on the Ethnic Classification of Idiots'. He classified Down syndrome as being the 'Mongolian type of idiot'. However, it was J�r�me Lejeune, in 1959, who discovered which chromosome causes Down syndrome. Which chromosome is it?

Answer: 21st

Trisomy 21 is an alternate name for Down syndrome. The word trisomy means to have one or more sets of three chromosomes, as opposed to two which is the norm. The number following it refers to the affected chromosome which in this case is 21. Trisomy 21 occurs when a sperm or egg cell (gamete) is produced with an extra copy of chromosome 21 which means the gamete has 24 chromosomes. When this gamete combines with the normal gamete from the other parent, the embryo will have 47 chromosomes with three copies of the 21st chromosome.

John Langdon Down's terminology for Down syndrome is now said to have misleading connotations, as well as being an embarrassing term. The World Health Organisation officially dropped the term mongolism in 1965. However, it does still appear is some medical texts.

2. There are many different variations of Down syndrome with the most common accounting for around 95% of all recorded cases. Another form of the syndrome occurs when a segment of the 21st chromosome breaks off and attaches itself to another chromosome. What name is given to this form?

Answer: Translocation

Of all recorded cases of Down syndrome, only around 4% are the result of translocation, which can take on several different forms. Before translocation occurred, the baby would have had the normal number of chromosomes.

3. A third variation of Down syndrome accounts for around 1 - 2% of all recorded cases. In this form, there is a chance that the individual will have less prominent physical features of Down syndrome. What is this form called?

Answer: Mosaic

In Trisomy 21, which is the most common form of Down syndrome, all of the cells within the body are affected by the additional chromosome. In mosaicism, there is a mixture of cells affected by trisomy 21 and cells with the normal number of chromosome.

The name comes from the fact that, in mosaicism, the cells form a mosaic pattern within the body.

4. There are many physical attributes which are common to individuals who have Down syndrome. However, many of these attributes can also appear on people who do not have the syndrome. Below I have listed four attributes. Which one is not common to people who have Down syndrome?

Answer: Tall stature

An individual who has Down syndrome may have all or some of the characteristics. Typically individuals are short in stature with a short neck and poor muscle tone. They may also have an enlarged and protruding tongue due to a small oral cavity and the tongue being larger nearer the tonsils, Brushfield spots, which are white spots on the iris and an excessive space between the large and second toe.

5. Individuals with Down syndrome also have additional health concerns due to being at a higher risk of developing certain ailments. Which of the following are individuals with Down's NOT at high risk of developing?

Answer: Diabetic retinopathy

Although there are health problems which are associated with having Down syndrome, there are also health benefits. Having Down syndrome gives a reduced risk of developing many common malignancies. This does not, however, include leukaemia, which individuals are 15 - 30 times for likely to develop , and testicular cancer. It is unclear as to why the incidents of fatal cancers in reduced amongst individuals who have Down syndrome although it could be related to the tumour suppressor genes on the 21st chromosome.

Another explanation could be that individuals with Down are not as exposed to the environmental factors which increase the risk of some cancers.

6. It is not possible to prevent the genetic abnormality which causes Down syndrome. However, it has become easier to identify babies who are at risk during pregnancy. Test which can indicate a risk of Down include, a triple screen which is offered at 15 - 20 weeks of detection, a quad screen which is also offered at 15 -20 weeks and a nuchal translucency test which is offered between 10 - 13.5 weeks. What does the nuchal translucency test measure?

Answer: The width of the spinal cord at the back of the baby's neck

The test requires an ultrasound, which measures the amount of fluid at the back of the baby's neck; this tends to be higher in babies who have Down syndrome. Although it detects around 62% of all cases of Down syndrome, there is a small chance of a false positive being given. Therefore, an amniocentesis is needed to confirm a genetic abnormality. However, due to it being an invasive procedure, which involves taking amniotic fluid from the amniotic sac, it does come with a risk of miscarriage.

An amniocentesis may also be used to diagnosis trisomy 18 (Edwards syndrome) and spina bifida.

7. Down syndrome affects people from all cultures and ethnic groups and, in many cases, is sporadic. This means that neither of the parents are affected by the disorder and that the chances of any other pregnancies resulting in a Down syndrome baby are slim. However, there are factors which can increase the risk. Which of the following is one of them?

Answer: The age of the mother

Although the risk of an infant having Down syndrome does increase with age, most babies with the syndrome are born to younger parents. This is due to most people choosing to have their children at a young age. At the age of 20, a woman's chance of having an child with Down is about 1 in 1700. This increases to 1 - 900 at age 30, 1 in 100 at age 40 and 1 -35 at age 45.
The age of the father may also have an effect of the likelihood of conceiving a child who has Down syndrome.

8. Although an amniocentesis may suggest that an infant has Down syndrome, it cannot be properly confirmed until after the baby has been born. This is usually done within the first few days following the birth. What method can be used for diagnosis?

Answer: Karyotype

Medical professionals are trained to notice the physical characteristics which are associated with the syndrome but this is not always straight forward due to the fact not all infants show the physical traits.

A karyotype is a blood or tissue sample which is stained in order to show chromosomes grouped by size, number and shape. This can be used in order to verify the diagnosis of Down syndrome.

9. It is important for individuals with Down syndrome to receive proper education regarding sexuality, as they are perfectly entitled to embark on personal and sexual relationships of their own. They also need to receive advice regarding contraceptives. Would a person with Down syndrome be able to conceive a child?

Answer: Yes

Although there is a reduced fertility rate, a couple, with either one or both people having Down syndrome, could conceive a child of their own. However, because of their learning difficulties they may make the decision not to have children. There are many factors which could result in this decision such as the financial strain and the work involved with raising a child. The chance of a baby having Down's syndrome is raised if one of the parent's has it themselves and is higher again if both do.

If a pregnancy was to occur in a female who has Down syndrome, there is a high risk of a miscarriage or giving birth to a premature baby. A caesarean section may also be needed in order to deliver the baby.

10. Individuals who have Down syndrome have a life expectancy of 50 - 60+ years of age, although this can be lessened if the individual has significant health problems. This has increased from 15 years in the 1950s. As the life expectancy of individuals with Down syndrome has increased, a link has emerged between it and another disorder. Individuals with Down syndrome have a 50% chance of developing this other disorder. What is the disorder?

Answer: Dementia

Diagnosis of dementia in individuals who have Down syndrome can prove difficult, as there are medical reasons why an individual may exhibit the signs of having dementia. Generally, the first outward sign is a change in memory. However, for people with Down syndrome, it is often a change in their behaviour. This, for example, could be a normally placid person becoming increasingly more angry and aggressive.

In people who have Down syndrome, dementia tends to progress at a more rapid rate. This means it is extremely important to diagnose it in the early stages, because this is when treatment is most effective at slowing the effects.

Source: Author NoseTwitcher14

This quiz was reviewed by FunTrivia editor crisw before going online.
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Down Syndrome Trivia Quiz

Down syndrome is a chromosomal disorder. How much do you know about it?

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