Bone Diseases

Question 1

what is the most likely mode of inheritance of achrondoplasia?

Answer 1

Autosomal dominant

Question 2

Is the mutated form of FGFR3 active or inactive in achondroplasia?

Answer 2

In achondroplasia, the mutated form of the receptor is active and this leads to severely shortened bones

Question 3

What are the clinical features of osteogenesis imperfecta?

Answer 3

blue sclerae, low bone mineral density

Question 4

What is the difference between osteomalacia and osteoporosis?

Answer 4

Osteoporosis: net bone loss
Osteomalacia: increase in ratio of unmineralized to mineralized bone.

Question 5

What is sclerostin?

Answer 5

Puts a brake on bone formation. Inhibits osteoblasts and activates osteoclasts

Question 6

What effect does metabolic acidosis have on bone formation

Answer 6

Increase bone resorption by:

1. Increase in H+ directly activates osteoclasts.
2. Acidosis is constantly corrected by kidney leading to kidney failure, leading to failure to create calcitriol, no osteoblasts activated.

Question 7

A health problem that results from maternal iodine deficiency and is characterised by disproportionally short limbs, large head due to delayed closure of fontanelles and mental impairment is……

Answer 7

Cretinism

Question 8

Name a few enzymes which increase osteoclasts function

Answer 8

IL 1,6
Tumor Necrosis Factor alpha
Macrophage colony stimulating factor
Rank ligand

Question 9

What are Wnt proteins?

Answer 9

these are signaling molecules that cause osteoblast differentiation. Their action is blocked by sclerostin.

Question 10

State the treatments of osteoporosis

Answer 10

Hormonal and non hormonal.
Hormonal: low level estrogen and intermittent PTH.
Non hormonal: Bisphosphonstes and Rank Ligand antibody.