Blount disease

What it is

A rare primary bone dysplasia characterized by disordered endochondral ossification of the medial part of the proximal tibial physis leading to multiplanar deformities of the lower limb. Patients present with bow-legged deformity with bone angulation just below the knee which is mostly bilateral. Severe deformity may result in early degenerative arthritis of the knee. It may occur as an isolated condition or as a part of a syndrome. It mostly occurs in infancy, however adolescence-onset patients have also been reported. Risk factors may include obesity and early walking.

Key facts

Age of onset

Childhood, Infancy

Inheritance

Autosomal recessive

Classified as

Malformation syndrome

Signs and symptoms

These ranges are how often a sign appears across everyone diagnosed, not a prediction for one person — most people have some of these and not others. Orphanet also records findings that are specifically absent in this disease; those are in the data but not listed here.

ICD-10 codes

ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.

Cross-references