PRDM8-related progressive myoclonus…

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PRDM8-related progressive myoclonus epilepsy

ORPHA:324290Disease

Also called Early-onset Lafora body disease

What it is

A rare genetic progressive myoclonic epilepsy characterized by childhood onset of progressive dysarthria, myoclonus, ataxia, seizures, and cognitive decline. The disease takes a protracted course with patients surviving into adulthood, developing signs and symptoms like psychosis with outbursts of prolonged agitation and screaming, spasticity and hyperreflexia, confusion, mutism, and incontinence. There are no visual disturbances. Muscle biopsy shows numerous periodic acid-Schiff-positive inclusions, so-called Lafora bodies.

Key facts

Prevalence
<1 / 1 000 000
Age of onset
Childhood
Inheritance
Autosomal recessive
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.

Gene

PRDM8Disease-causing germline mutation(s)

ICD-10 codes

G40.3filed under a broader ICD-10 category — shared with 22 other rare diseases

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

MONDO 0014717OMIM 616640UMLS C4518574

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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