The investigative workup for progressive myoclonic epilepsies
| Disorder | Investigations | |
|---|---|---|
| 1. | Unverricht–Lundborg disease (EPM1) | Gene test: EPM1 (CSTB) mutation analysis |
| 2. | Lafora body disease (EPM2) | 1. Skin biopsy: Lafora bodies 2. Gene tests: EPM2A or EPM2B (NHLRC1) mutation analysis |
| 3. | Action myoclonus renal failure syndrome (EPM4) | Gene test: SCARB2/LIMP2 mutation analysis |
| 4. | PRICKLE1-related progressive myoclonus epilepsy with ataxia (EPM5) | Gene test: PRICKLE1 mutation analysis |
| 5. | ‘North Sea’ progressive myoclonus epilepsy (EPM6) | Gene test: GOSR2 mutation analysis |
| 6. | MERRF | 1. Plasma lactate, pyruvate (as screen) 2. Muscle biopsy: for ragged-red fibres 3. Gene test: MT-TK mutation analysis |
| 7. | Neuronal ceroid lipofuscinosis (CLN) | 1. Skin biopsy (electron microscopy): curvilinear profiles, fingerprint profiles, granular osmophilic deposits 2. Leucocyte enzyme analysis (PPT1,TPP1, CTSD) 3. Gene tests: PPT1, TPP1, CLN3, CLN5, CLN6, MFSD8, CLN8, CTSD, DNAJC5, CTSF, ATP13A2, GRN, KCTD7 mutation analysis |
| 8. | DRPLA | Gene test: DRPLA mutation analysis (CAG repeats) |
| 9. | Sialidosis type I (cherry-red spot myoclonus syndrome) | 1. Sialo-oligosaccharides in urine 2. Leucocyte enzyme analysis (neuraminidase) 3. Gene test: NEU1 mutation analysis |
| 10. | Tay–Sachs disease (GM2 gangliosidosis) | 1. Leucocyte enzyme analysis (hexosaminidase A, B) 2. Gene test: HEXA mutation analysis |
| 11. | Gaucher's disease | 1. Leucocyte enzyme analysis (β-glucocerebrosidase) 2. Gene test: GBA mutation analysis |
DRPLA, dentatorubral-pallidoluysian atrophy; EPM, progressive myoclonus epilepsy.