MSK deformities

Question 1

What are the most common forms of skeletal dysplasia

Answer 1

Achondroplasia
Hypochondroplasia

Question 2

What is the aetiology of achondroplasia

Answer 2

Autosomal dominant BUT 70% sporadic mutations in fibroblast growth factor receptor 3 (FGFR3)

Question 3

What are the signs and symptoms of achondroplasia

Answer 3

Short stature, shortening of limbs (Rhizomelia), ± hydrocephalus
Large head, frontal bossing
Depression of nasal bridge
Short, broad hands
Marked lumbar lordosis
‘Trident Hands’

Question 4

Define dwarfism

Answer 4

height less than 2 S.D. below the mean

Question 5

What are the signs and symptoms of hypochondroplasia

Answer 5

Small stature
Micromelia (small extremities)
Large head

Question 6

What is SHOX

Answer 6

Short stature homeobox gene
Seen in Turner’s (1 less) and klinefelters (>2 SHOX)
X-linked

Question 7

What is osteogenesis imperfecta

Answer 7

S/S: blue sclera, short stature, loose joints, hearing loss, breathing problems
Types = 7 forms
- Most common: type 1 = abnormal pro-alpha 1 or 2 collagen polypeptides

Question 8

What investigations should be done for achondroplasia

Answer 8

Prenatal scans (not apparent until more than 22w GA so may be missed)
Clinical diagnosis (and XR findings)
- Metaphyseal irregularity (inverted V metaphysis = ‘chevron deformity’
- Flaring in long bones, late-appearing irregular epiphyses
Molecular analysis confirmation

Question 9

What are the complications of achondroplasia

Answer 9

Gross motor skill delay
Kyphosis
Early osteoarthritis
Risks from hydrocephalus
Obesity
ENT issues