Sialuria (MIM:269921) is caused by a metabolic defect where ...

created [InstanceEdit:4088407] Jassal, B, 2013-08-13
dbId 4088330
displayName Sialuria (MIM:269921) is caused by a metabolic defect where ...
modified [InstanceEdit:5690643] Jassal, Bijay, 2015-04-30
schemaClass Summation
text Sialuria (MIM:269921) is caused by a metabolic defect where the UDP?N?acetylglucosamine 2?epimerase, N?acetylmannosamine kinase (GNE) gene lacks feedback inhibition resulting in constitutive overproduction of free sialic acid (Neu5Ac) (Montreuil et al. 1968, Fontaine et al. 1968). Sialuria is characterised by a large cytoplasmic accumulation and urinary excretion of Neu5Ac (Kamerling et al. 1979). Sialurias differ from sialidoses, in which there is storage and excretion of 'bound' Neu5Ac. Defects in GNE also cause Nonaka myopathy (NK; MIM:605820), an early adult-onset disorder characterised by muscle weakness and wasting of distal muscles, especially the anterior tibial muscles (Nonaka et al. 1981, Asaka et al. 2001). Defects in GNE also cause inclusion body myopathy 2 (IBM2; MIM:600737), an autosomal recessive disorder with a similar phenotype to Nonaka myopathy (NK). IBM2 is an adult-onset, proximal and distal muscle weakness and wasting disorder. Muscle biospsy reveals from sufferers shows a rimmed vacuole myopathy and the degenerating muscle fibers contained abnormal amounts of beta-amyloid protein such as that found in neurodegenerative diorders. However, there is no neurological symptoms in these patients (Argov & Yarom 1984).
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