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Start free with EleplanLate-onset distal myopathy, Markesbery-Griggs type
ORPHA:98912Disease
Also called ZASP-related myofibrillar myopathy
What it is
A rare, genetic, non-dystrophic myofibrillar myopathy disorder characterized by late-adult onset of distal and/or proximal limb muscle weakness with initial involvement of posterior lower leg muscles, medial gastrocnemius and soleus. Patients present with ankle weakness followed by weakness of finger and wrist extensors and later on of proximal muscles. Ambulation is usually preserved. Late-onset associated cardiomyopathy and/or neuropathy has been reported in a minority of cases.
Key facts
- Prevalence
- <1 / 1 000 000
- Age of onset
- Adult
- Inheritance
- Autosomal dominant
- 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
Common30–79%
3Sometimes5–29%
6These 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.
Gene
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.
Related health topics
Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.
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
Orphadata Science: Free access data from Orphanet. © INSERM 1999. Data version 2026-06-23. Available under CC BY 4.0. This is a reference, not medical advice.
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