Clinical Picture
Young woman with progressive myoclonus epilepsy. No (!) cutaneous clinical findings. Skin biopsy prefered as the most convenient and least invasive method of establishing  the diagnosis of Lafora disease.

Histopathology
The inclusion bodies (Lafora bodies, polyglucosan bodies) are well seen in the excretoryducts of eccrine and apocrine sweat glands and peripheral nerves of clinically normal skin. They are PAS positive and diastase resistant. The number of inclusions may vary with the biopsy site.

Discussion
Lafora disease (Unverricht's disease, myoclonic epilepsy) is a familial, degenerative disorder with the clinical triad of seizures, myoclonus and dementia. Cutaneous lesions are rarely present. The enzyme defect is currently unknown, but the disease is usually regarded as an inborn error of carbohydrate metabolism. The intracytoplasmic inclusion bodies found in various organs, particularly in ganglion cells in parts of the brain, are glucose polymers; they were first described by Lafora, who considered them to consist of amyloid.

Diagnosis                             Lafora Disease

References

Newton GA et al. (1987)
Lafora's disease. The role of skin biopsy.
Arch Dermatol 123:1667-1669

Carpenter S (1987)
Skin biopsy for diagnosis of hereditary neurologic metabolic disease.
Arch Dermatol 123:1618-1621