A new metabolic muscle disease due to abnormal hexokinase activity.
A 34 year old man presented with an 8 year history of mild muscle pain and stiffness on exertion especially in the cold. Clinical examination was normal. Apart from a mild persistent leucocytosis, his routine investigations were normal including creatine kinase activity, electromyography and nerve conduction studies. An ischaemic exercise test produced a slow and incomplete rise in lactate. Histological examination showed non-specific myopathic changes in some quadriceps femoris muscle fibres. Investigation of muscle metabolism by spectrofluorometric analysis of muscle enzyme activity and by muscle fibre incubation studies revealed a severe defect in glucose phosphorylation, associated with an electrophoretically abnormal hexokinase. Further metabolic studies suggest that the block in glucose metabolism is by-passed via an enhanced phosphorylation of fructose by the abnormal hexokinase.
Poulton
K R
KR
Midland Centre for Neurosurgery and Neurology, Smethwick, West Midlands, UK.
Nightingale
S
S
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D005080:Exercise Test; D006593:Hexokinase / Q000172:deficiency* / Q000235:genetics; D006801:Humans; D008297:Male; D009132:Muscles / Q000201:enzymology; D009135:Muscular Diseases / Q000201:enzymology* / Q000235:genetics
D001786:Blood Glucose; D006593:Hexokinase