Internal Medicine

0521779407-08 CUNY1086/Karliner 0 521 77940 7 June 13, 2007 7:47

Galactosemia 597

transfusion; wait 3 months to perform confirmatory enzymology if

transfused)

■GALT immunoelectrophoresis determines genotype (G/G=classic

galactosemia, D/G=Duarte variant)

Other Tests

■serum amino acids (esp. phenylalanine, tyrosine, methionine) may

be elevated when liver disease is present; elevated phenylalanine

may lead to false positive newborn screen for phenylketonuria

■viral serology negative

■liver biopsy: non-specific ‘neonatal hepatitis’

■DNA analysis not routine, but may be available in some centers

■prenatal diagnosis by GALT activity or mutation analysis in amnio-

cytes or chorionic villi possible

Imaging

■abdominal ultrasound: non-specific

differential diagnosis

■Duarte/Galactosemia heterozygosity, Duarte allele 50% normal

activity, D/G heterozygotes∼25% normal activity, not at risk for clas-

sic galactosemia complications, some treat in infancy with galactose

restriction (controversial)

■galactokinase deficiency: cataracts, pseudotumor cerebri (rare), no

liver disease, urine reducing substances positive (after galactose

ingestion), blood & urine with increased galactose, decreased ery-

throcyte galactokinase, normal erythrocyte GALT activity

■uridyl diphosphate:galactose epimerase deficiency: signs & symp-

toms similar to galactosemia, increased erythrocyte galactose-1-

phosphate, decreased erythrocyte epimerase activity, normal ery-

throcyte GALT activity

■other causes of ‘neonatal hepatitis’: alpha 1 antitrypsin deficiency,

cystic fibrosis, tyrosinemia, neonatal hemochromatosis, glycogen

storage disease type IV, bile acid disorders, fatty acid oxidation

defects, congenital disorders of glycosylation, peroxisomal disor-

ders, Niemann-Pick disease type C, hereditary fructose intolerance

management

What to Do First

■monitor closely for neonatal sepsis

■evaluate severity of liver, renal, CNS disease