Down Syndrome

Question 1

Down syndrome, also referred to as trisomy results in a patient have 3 chromosomes. Patients with down syndrome have 47 chromosomes, what is the additional chromosome?

1 - chromosomes 21
2 - chromosomes 13
3 - chromosomes
4 - chromosomes 10

Answer 1

1 - chromosomes 21

13 = Patau syndrome
18 = Edward syndrome

Question 2

Down syndrome, also referred to as trisomy is due to an additional chromosomes 21. This is the most common chromosomal abnormality. How many births have this?

1 - 1 in 70
2 - 1 in 700
3 - 1 in 7000
4 - 1 in 70,000

Answer 2

2 - 1 in 700

Slightly higher in males

Question 3

Down syndrome, also referred to as trisomy is due to an additional chromosomes 21. What is the most common cause of down syndrome?

1 - Robertsonian translocation
2 - Nondisjunction
3 - Mosaicism
4 - all are equally likely

Answer 3

2 - Nondisjunction
- accounts for 94% of cases

Nondisjunction = failure of the chromosomes to separate
Robertsonian translocation = chromosomes fuse together
Mosaicism = 2 sets of different cells in the body

Question 4

Which of the following is the strongest risk factor for down syndrome?

1 - pre-eclampsia
2 - pre-term birth
3 - obesity
4 - maternal age

Answer 4

4 - age

Risk increases as we age

Question 5

Which of the following is NOT a typical feature of a patient with down syndrome?

1 - upward slanted eyes
2 - cleft lift
3 - single crease across the palm of the hand/foot
4 - flattened facial profile
5 - flat occiput (back of the head)

Answer 5

2 - cleft lift

Question 6

Which of the following is NOT a clinical sign of down syndrome?

1 - intellectual disability
2 - developmental delays (growth and mental)
3 - increased risk of congenital heart defects, hearing loss (otitis media and glue ear), eye problems, Hirschsprung’s disease and thyroid problems (hypothyroidism)
4 - inflammatory bowel disease
5 - duodenal atresia (blockage of bowel)

Answer 6

4 - inflammatory bowel disease

Heart = septal defects

Hirschsprung’s disease = rare disorder of the bowel, most commonly the large bowel (colon), which can lead to severe constipation and intestinal obstruction

Question 7

Do patients with down syndrome typically present with increased or decreased fertility?

Answer 7

• decreased fertility

Question 8

Which of the following neurological conditions are down syndrome patients likely to develop?

1 - Parkinsons disease
2 - Alzheimer’s disease
3 - Guillain–Barré syndrome
4 - Myasthenia gravis

Answer 8

2 - Alzheimer’s disease

Question 9

Which test is typically the first line test for diagnosing down syndrome?

1 - serum genetic testing
2 - amniocentesis
3 - combined test
4 - chorionic villus sampling

Answer 9

3 - combined test

• blood test = serum B-HCG + pregnancy associated plasma protein A
• ultrasound = measure nuchal translucency

Question 10

If the combined test is inconclusive when trying to diagnose down syndrome, we can do the triple test. Which of the following is NOT part of the triple test?

1 - inhibin-A
2 - alpha-fetoprotein
3 - unconjugated oestriol
4 - human chorionic gonadotrophin

Answer 10

1 - inhibin-A

Part of quadrupole test

Question 11

If the combined test is inconclusive when trying to diagnose down syndrome, we can do the quadruple test. Which of the following is part NOT part of the quadruple test?

1 - inhibin-A
2 - alpha-fetoprotein
3 - unconjugated oestriol
4 - human chorionic gonadotrophin
5 - foetal haemoglobin

Answer 11

5 - foetal haemoglobin