The aim of this study is to investigate pharmacokinetics and safety of N-acetylneuraminic
acid in patients with Distal myopathy with rimmed vacuoles (DMRV) - hereditary inclusion body
myopathy (hIBM). Dosages are 800mg single and three times a day and 800mg 3 times a day for 5
consecutive days. N-acetylneuraminic acid and N-glycolylneuraminic acid in serum and urine
are measured before and after oral administration of N-acetylneuraminic acid.