Studies on b-aminoisobutyric aciduria of Korean population

The urinary BAlB concentration of Korean population was assayed using high voltage electrophorebis with Whatman 3MM filter paper, and the BAlB concentration in urine was expressed on the basis of creatinine content. The survey of twins and families was also made concerning the urinary BAlB excretion. The results obtained are as follows. 1) No appreciable daily fluctuation of BAIB concentration was observed for seven consecutive days in the same individual with 6 persons examined. 2) The BAlB concentration'varies individually in the extreme from 0 to 211ftg/mg creatinine. The evident bimodality was demonstrated in the distribution of its concentration of 570 subjects above 11 years of age, though two modes overlapping, and the same held for both 326 males and 244 females. Assuming a symmetrical curve in the higher mode, the approximate division line was made at 1. 7 (log 50), and thus 50l'g/mg creatinine of BAIB was provisionally set as dividing amount between high and low excretors. 3) 570 subjects of both sexes above 11 years of age exhibited high excretors of 14.7% with same value in 326 males and in 244 females. The frequency of high excretors was thus shown to be higher than that of Caucasoid population but lower than that of other Oriental peoples except Eskimo. 4) The BAIB concentration in urine was higher in children group below 10 years of age than that in other group above 11 years of age. 5) The urinary BAIB concentration was quite similar in each pair of 5 twins except one, suggesting genetic control of BAIB excretion. 6) The BAIB excretion was surveyed on 21 families. Offspring of 34 low excretors and 13 high excretors were born from 19 low excretor parents, and the lower the BAIB concentration in low excretor parents, the more the low excretor offspring were produced. This family study also suggests the involvement of hereditary factor in urinary BAIB excretion. 7) Discussion was attempted on the BAIB metabolism. Acknowledgements This study was supported by the research grant (1972) from the Ministry of Education to whom we are very grateful