| Research Abstract |
The subjects in newborn screening pilot study using tandem mass spectrometry were investigated in order to establish the practical screening system in Japan.
The tentative cutoff values were tested using the dried blood spots of the patients with target disorders in this project, such as multiple acyl-CoA dehydrogenation defect (GA-II), medium-chain acyl-CoA dehydrogenase (MCAD) deficiency, very-long-chain aryl-CoA dehydrogenase deficiency, and multiple carboxylase deficiency. The ratios of propionylcarnitine to acetylcarnitine were shown to be better marker for the screening of propionic academia and calssical methylmalonic aciduria.
The severity of the diseases in patients found in this screening were estimated by the measurement of enzyme activities and the analysis of DNA mutation, which were done in cooperation with the researchers in Hiroshima University and Kyoto University. Therapies for the patients were conducted based on the results in this categories, and almost all patients, except for those with the severest form of the disease, are in good condition.
The methods were modified using rust-free N2 drier and less expensive reagent to improve the sample quality and cost burden.
We have analyzed about 200,000 dried blood spots and found 25 patients, which enable us to estimate the frequency of target diseases in Japan. In Japan, organic acidemias, such as propionic acidemia and glutaric aciduia type I, are relatively common, and fatty acid oxidation disorders, such as MCAD defiency and GA-II, are not so rare as believed before. It is suggested that screening system in Japan, including medical care for the patients, should be modified for such target diseases.
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