| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2005: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2004: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Research Abstract |
In newborn screening pilot study by tandem mass spectrometry (MS/MS), we have found 35 patients among about 300,000 newborns (1:8,400 in prevalence) and clarified the significance of this screening in Japan. We also demonstrated the excellent accuracy of this screening system ; false positive rate was 0.09% and 16% of recall cases were the patients during the last two years. Patients with organic acidemias, such as propionic acidemia, methylmalonic acidemia and glutaric aciduria type I, were the most prevalent, and those with fatty acid oxidation disorders were not rare at all. Most patients have been treated successfully by diet therapies and prevention of fasting.
We have found two patients with SCAD deficiency based on high C4-acylcarnitine levels and elevated urinary ethylmalonic acid. This disorder, however, has been omitted because of the presence of healthy siblings with this disorder and of the difficulties in differential diagnosis.
We have tested the second-tier screening for hereditary tyrosinemia type I using enzymatic assay of succinylacetone in newborns with elevated tyrosine, and found the insufficient accuracy of this method. It is thought that the accurate methods for primary screening should be tried since the patients without elevated tyrosine in dried blood spots.
Among 7 patients with citrin deficiency, 4 patients were detected in MS/MS screening with the indices ofincreased citrulline levels together with abnormal profile of the other designated amino acids. The other 3 patients had normal amino acid profile, while one had high galactose levels, in newborn blood spots.
We have measured serum levels of acylcarnitines and organic acids in our patients to evaluate their conditions under our therapeutic strategy, which was thought to be beneficial for their excellent development based on the low ratios of toxic organic acids to free carnitine, especially, in 3 patients with glutaric aciduria type I.
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