genu valgum

Multiple Hereditary Exostosis

Diaphyseal Aclasis / Multiple Osteochondromas

Heritable skeletal dysplasia

AD with variable penetrance (96%)

Incidence of malignant transformation much higher

- 10% overall

- 1 % / year

Chondrosarcoma (CS) > Osteosarcoma (OS)

Disturbance of endochrondral ossification of epiphyses of tubular bones

- preservation of vertebrae (c.f. SED)

Dysproportionate dwarfism with normal trunk

- not as severe as achondroplasia

- usually 145 - 170 cm tall

Characterised by small flattened irregular epiphyses

- symmetrical

- leads to OA by 3-4th decade