Immune-mediated necrotizing myopathy

What it is

A rare form of idiopathic inflammatory myopathy characterized by acute or subacute, severe, symmetrical, proximal muscle weakness usually associated with muscle-specific antibodies (anti-HMGCR or anti-SRP). Histopathological characteristics include myocyte necrosis and regeneration without significant inflammation, and C5b-9 deposition on non-necrotic myofibers.

Key facts

Prevalence

1-9 / 100 000

Age of onset

Adolescent, Adult, Childhood, Elderly

Inheritance

Not applicable

Classified as

Disease

Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.

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.

Benefit programs to look at

Programs whose eligibility touches the same ICD-10 categories. Eligibility is decided by the administering agency, never by this page.

Cross-references