A/48

Question 1

Examples of autosomal dominant disorders (5)

Answer 1

• familial hypercholesterolemia
• polycystic kidney disease
• hereditary spherocytosis
• marfan syndroe
• huntington disease

Question 2

Abnormal protein in familial hypercholesterolemia?

Answer 2

LDL receptor

Question 3

Abnormal protein in marfan syndrome?

Answer 3

fibrillin glycoprotein

Question 4

Abnormal protein in ehlers danlos syndrome?

Answer 4

collagen

Question 5

Abnormal protein in hereditary spherocytosis?

Answer 5

spectrin, ankyrin or protein 4.1

Question 6

Abnormal protein in polycystic kidney disease?

Answer 6

Polycystin-I (PKD-1)

Question 7

What factors can modify the clinical features of the disorder?

Answer 7

• reduced penetrance

- variable expressivity

Question 8

When do clinical signs / symptoms appear?

Answer 8

they appear with a 50% loss of enzyme activity

Question 9

Which gene codes for fibrillin? Where is it?

Answer 9

FBN1 gene (15q21)

Question 10

Prevalence of Marfan syndrome?

Answer 10

1 / 5000

Question 11

Which tissues are most affected by marfan syndrome?

Answer 11

• aorta
• ligaments
• ciliary zonules
• bone

Question 12

Why are bones affected by marfan syndrome?

Answer 12

because the mutation results in overproduction of TFG beta, which causes overgrowth

Question 13

Main clinical presentations of marfan syndrome? (3)

Answer 13

• skeletal abnormalities
• ocular change
• cardiovascular system

Question 14

Skeletal abnormalities in marfan syndrome? (4)

Answer 14

• slender body
• long limbs
• kyphoscoliosis
• hyperextendable joints

Question 15

Cardiovascular system abnormalities in marfan syndrome?

Answer 15

• aortic dissection

- floppy valve syndrome (regurgitation)

Question 16

Molecular basis of ehlers-danlos syndrome (3)

Answer 16

• deficiency of type III collagen synthesis due to COL3A1 gene mutation
• deficiency of type V collagen synthesis due to COL5A1 and COL5A2 gene mutation