Achondroplasoa

Question 1

Achindroplasia is the result of a heterozygous mutation in what gene?

Answer 1

FGFR3 on chromosome 4

Question 2

Most cases of achondroplasia are the result of a sporadic mutation but some cases are inherited. T/F?

Answer 2

True

Question 3

In achondroplasia there is a mutation in FGFR3 where there is a swap in the 380th amino acid from what to what?

Answer 3

Glycine for arginine

Question 4

How does the FGFRe mutation lead to achondroplasia?

Answer 4

The mutation stabilises FGFR3 dimers to cause the constitutive expression of the receptor. The active receptor can induce the signal transducer and activator of transcription one pathway to inhibit chondrocyte proliferation
The active receptor can also induce mitogen activated protein kinase pathway to negatively affect proliferation and terminal differentiation of chondrocytes

Question 5

What are the characteristics of achondroplasia?

Answer 5

Proximal Shortened long bones
Varus leg deformity
Brachydactyly
Large head size
Frontal bossing
Flattened nasal bridge
Narrowed foramen magnum
Spinal lordosis