Close help

How to use this Learning Station

On this Learning Station, you can read and test your knowledge. Tap on a book to open its chapter list. In each chapter, you can take a quiz to test your knowledge.

To take tests, you must register with your email address or cell number. It is free to register and to take tests.

For help email or call +27 76 657 0353.

Printed books

Learning is easiest with printed books. To order printed books, email or call +27 76 657 0353.

Visit for information.

Test 4: Single gene disorders

  1. Oculocutaneous albinism, Waardenburg syndrome and haemophilia are inherited as:
    • Single gene defects.
    • Multifactorial disorders.
    • Congenital disorders due to a teratogen.
    • Trisomies.
  2. Waardenburg syndrome is inherited as:
    • An autosomal dominant disorder.
    • An autosomal recessive disorder.
    • An X-linked recessive disorder.
    • A chromosomal abnormality.
  3. What is an important feature of Waardenburg syndrome?
    • Very blue eyes.
    • Pale skin.
    • Intellectual disability.
    • Slow growth.
  4. The main complication of Waardenburg syndrome is:
    • Severe sun damage.
    • Convulsions.
    • Severe deafness.
    • Blindness.
  5. The risk of a child having Waardenburg syndrome if one of the parents is affected is:
    • Very small.
    • 25%.
    • 50%.
    • 100%.
  6. How is oculocutaneous albinism inherited?
    • As an autosomal dominant disorder.
    • As an autosomal recessive disorder.
    • As an X-linked recessive disorder.
    • As a chromosomal abnormality.
  7. How common is oculocutaneous albinism in South Africa?
    • About 1 per 1000 live births.
    • About 1 per 4000 live births.
    • About 1 per 10 000 live births.
    • About 1 per 50 000 live births.
  8. What are the main features of oculocutaneous albinism?
    • Light-coloured eyes only.
    • Pale skin.
    • Both pale skin and light eyes.
    • Pale skin and hair with light eyes.
  9. People with oculocutaneous albinism have serious problems with:
    • Hearing.
    • Vision.
    • Hearing and speech.
    • Hearing, speech and vision.
  10. What is a major complication of oculocutaneous albinism?
    • Skin cancer.
    • Leukaemia.
    • Cancer of the eye.
    • Cancer of the liver.
  11. Patients with oculocutaneous albinism often are:
    • Intellectually disabled.
    • Visually disabled.
    • Crippled due to joint damage.
    • Socially isolated.
  12. Important care in patients with oculocutaneous albinism includes:
    • Sun protection at all times.
    • Prophylactic antibiotics.
    • Special diet high in protein.
    • A hearing aid.
  13. What is the cause of haemophilia?
    • Too few platelets in the blood.
    • Lack of normal blood clotting factors VIII or IX.
    • Too few red cells in the blood.
    • Lack of vitamin K.
  14. Haemophilia is inherited as:
    • An autosomal dominant disorder.
    • An autosomal recessive disorder.
    • An X-linked recessive disorder.
    • A chromosomal abnormality.
  15. Mild haemophilia is seen:
    • Only in boys.
    • Only in girls.
    • Mostly in boys.
    • Mostly in girls.
  16. What blood test can be used to screen for moderate or severe haemophilia?
    • The international Normalised Ratio (INR).
    • The partial thromboplastin time (PTT).
    • A platelet count.
    • The haemoglobin concentration.
  17. What is a common complication of severe haemophilia?
    • Haemarthroses (bleeds into joints).
    • Intracranial haemorrhages.
    • Blood in the stool.
    • Vomiting blood.
  18. What is the management of a child with haemophilia who presents with a haematoma (bleed into a muscle)?
    • Reassure the mother that it will recover over the next week.
    • Place ice over the site of the bleed and give the child two aspirin.
    • Start a blood transfusion.
    • Start a transfusion of factor VIII or IX.
  19. What is the risk for parents who have two sons with haemophilia having another affected child in future pregnancies?
    • Very small.
    • 10% if it is a boy.
    • 50% if it is a boy.
    • All their future children are likely to be affected.
  20. If the father has haemophilia, what is the risk of his sons having haemophilia also?
    • Nil.
    • 1:4.
    • 1:2.
    • 1:1 (100%).