アミノ酸代謝異常酵素障害の多様性と脳障害

抄録

Rapid development of analytic procedure for amino acid since 1950 has been accompanied with the discovery of more than forty new disorders of amino acid metabolism. Although the phenotypic condition in metabolic disorder may be influenced by environmental factors, such as excess of amino acid intake, vitamin deficiency, damage of blood-brain barrier and others, the screening of large populations of newborn infants for the metabolic disease has led to the discovery of phenotypic and genotypic heterogeneity in metabolic disorders of amino acid.
According to the analytic study of phenylalanine metabolites in serum and urine of the patient with typical and atypical phenylketonuria by using gas-liquid chromatography, it was suggested that there would be several genotypic heterozygotes, homozygotes and also double heterozygotes.
The mass-screening of populations with established disease has discovered examples of more genetic disease of metabolism, however, some type of genetic disease associated with partial defect of isoenzymes or defect of an enzyme related to minor metabolic pathway may not be detected by usual screening procedure, because of no chemical abnormality in serum and urine. We may expect the fractionation of the various enzyme deficiencies into spectra of conditions, each with a different alteration in the enzyme.