Lafora disease is an inborn error of carbohydrate metabolism with storage of a polyglucosan in various tissues including brain and liver. Lafora disease is characterized by pathognomonic inclusions, Lafora bodies (LB), in neurons and other cell types.

Microscopic synopsis

 brain
 skin

• PAS-positive inclusions in numerous peripheral cells of eccrine sweat ducts, in eccrine sweat glands or in apocrine sweat glands (#6796905#, #14663053#)

 skeletal muscle
 peripheral nerve
 liver: hepatic Lafora disease (#2172143#)

• ground-glass hepatocytes due to inclusions (Lafora bodies) (#2172143#)

 heart

• third-degree atrioventricular block (#10593553#)
• cardiac arrhythmia (#10593553#)

Differential diagnosis

 Lafora-like bodies (Lafora body like inclusions)

• isolated (#2172143#)
• alcohol aversion therapy by cyanamide or disulfiram

 type IV glycogenosis (amylopectinosis)

Electron microscopy

 the inclusions consisted of polyglucosan-type material, not bounded by a membrane (#6791573#)

Etiology

 germline mutations in the EPM2A gene coding for laforin protein at 6q24
 germline mutations in the NHLRC1 gene coding for malin at 6p22.3

References

 Ganesh S, Puri R, Singh S, Mittal S, Dubey D. Recent advances in the molecular basis of Lafora's progressive myoclonus epilepsy. J Hum Genet. 2005 Nov 26; PMID: #16311711#

 Andrade DM, Ackerley CA, Minett TS, Teive HA, Bohlega S, Scherer SW, Minassian BA. Skin biopsy in Lafora disease: genotype-phenotype correlations and diagnostic pitfalls. Neurology. 2003 Dec 9;61(11):1611-4. PMID: #14663053#

 Ng IO, Sturgess RP, Williams R, Portmann B. Ground-glass hepatocytes with Lafora body like inclusions--histochemical, immunohistochemical and electronmicroscopic characterization. Histopathology. 1990 Aug;17(2):109-15. PMID: #2172143#