platyspondyly

Engelmann's Disease

Progressive diaphyseal dysplasia

- marked thickening of cortices of long bones

Present

Young child with gait disturbance and limb pain

Clinical

Bilateral symmetrical diaphyseal sclerosis of long bones

- Affects endosteal & periosteal new bone

- Metaphysis & epiphysis are normal

Skull base sclerotic

- can get blindness and deafness

Definition

Dysproportionate dwarfism

- short limbs and normal trunk

- rhizomelic

DDx

- physeal dysplasia (SED, MED)

Aetiology

FGF Receptor 3 

- point mutation

- decreases endochondral ossification

- normal intramembraneous ossification

- FGFR3 is found in all pre-bone cartilage & in CNS

- FGFR3 inhibits chondrocyte proliferation in the proliferative zone