Adult polyglucosan body disease body disease do not have identified mutations in the "GBE1" gene. In these individuals, the cause of the disease is unknown. Along with evaluation of the symptoms and a neurological examination, a diagnosis can be made based on genetic testing. Whether or not a person is making sufficient amounts of functional glycogen branching enzyme can be determined by taking a skin biopsy and testing for activity of the enzyme. Examination of tissue biopsied from the sural nerve under a microscope can reveal the presence of polyglucosan bodies. There will also be white matter changes visible in a magnetic resonance imaging
Brown blotch disease blotch disease causes large economic losses due to a perceived decrease in quality, even though it does not cause any health problems in humans. Brown blotch disease is observed in mushroom farms all over the world. In the UK, the Netherlands and France, 15% of the crop weight is affected by brown blotch disease, while in Italy it is even worse; in the worst years, 40% of the total weight of mushroom crops is affected by brown blotch disease in Italy. Because brown blotch disease affects all mushroom species, exotic mushrooms grown in eastern countries such as Japan, China, and