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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%).