• Journal of The Korean Society of Inherited Metabolic disease
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• v.12 no.1
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• pp.58-63
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• 2012

Classical galactosemia (OMIM# 230400) is an autosomal recessive disorder of carbohydrate metabolism, due to a complete loss in galactose-1-phosphate uridyltransferase (GALT; E.C.2.7.7.12) enzyme activity. It caused by mutations in the GALT gene (OMIM$^*$ 606999) that is located at chromosome 9p13. The GALT enzyme deficiency results in a build-up of galactose and galactose-1-phosphate, causing life threatening complications such as feeding problems, failure to thrive, hepatocellular damage, bleeding and sepsis. However, Duarte galactosemia, a variant form of GALT deficiency, has residual GALT enzyme activities in erythrocytes and do not have manifest the symptoms of classical galactosemia. Since the advent of newborn screening (NBS) for galactosemia, we rarely encounter such overwhelmingly ill newborns. The positive NBS with no symptoms indicates the possibility of Duarte galactosemia besides a simple false positive and it has to be differentiated from classical galactosemia which is a medical emergency. In Korea, detection rate of Duarte galactosemia is very low and its genetic information is restrictive, too. We report a case of monozygotic twins with D/G galactosemia compound heterozygote in proven by the mutational analysis of GALT gene, which revealed N314D polymorphism and -119 to -116 delGTCA.

• Clinical and Experimental Pediatrics
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• v.46 no.5
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• pp.440-446
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• 2003

Purpose : The genetic disturbance of galactosemia is expressed as a cellular deficiency of either galactose-1-phosphate uridyltransferase(GALT) or galactokinase(GALK) or UDP galactose 4-epimerase(GALE). To find-out the pattern of galactosemia in Korea, we retrospectively analyzed cases of galactosemia detected by neonatal screening program. Methods : We analyzed medical records of patients who visited Soonchunhyang University Hospital at age of 1 month after showing abnormalities in neonatal screening of galactosemia. For accurate diagnosis, galactose was measured by enzyme immunoassay(EIA) and fluorophotometer, also galactose-1-phosphate by fluorophotometer. Enzyme activities of GALK, GALT and GALE in RBC and galactose-1-phosphate were measured by radioisotope assay(RIA). Beutler test were done. Patients went on a lactose-free diet and follow-up tests for galactose, galactose-1-phosphate level and enzyme activity were performed. Results : 10 patients(male : 6, female : 4) were diagnosed as galactosemia. Two patients had GALK deficiency and two had GALT deficiency. Six were GALE deficient showing the largest number. In two patients with GALK deficiency, GALT and GALE activities were normal but GALK activities showed respectively reduced activity. For GALT deficiency, two patients had low GALT activity in RBC and showed genotype of Duarte 2/G(galactosemia) in DNA analysis. In one patient, GALT activity was normal. Three patients seemed to be heterozygote state of GALE deficiency according to GALE activity levels. Four patients showed GALK hyperactivity. Conclusion : GALE deficiency provided the highest number. After lactose-free diet, galactose and galactose-1-phosphate were normaly maintained. Neonatal screening on galactosemia is essential for preventing life-threatening symptoms and an accurate diagnosis is needed for finding out the type of galactosemia which is important for prognosis.