Experience of routine live-birth screening for galactosaemia in a British hospital, with emphasis on heterozygote detection

Galactosaemia: case for neonatal screening illustrated by recent Australian experience

The varied presentation and clinical features of classical galactosaemia are illustrated by the case histories of seven babies born in Western Australia since January, 1962, and of two babies born in South Australia in whom diagnosis was made as a result of adding galactosaemia to the Guthrie screening programme in October, 1974. All were shown to have a severe deficiency of galactose-1-phosphate uridyl transferase in their red blood cells. We compare our findings with those in 10 galactosaemic babies born in Victoria over a similar period, and show that in both groups these were two main modes of onset: acute and insidious. Jaundice and Escherichia coli infection were prominent in the 13 babies with an acute onset of galactosaemia, while poor weight gain, intermittent vomiting and cataracts were features of the five babies with an insidious onset. An enlarged liver was usually found in both groups. We discuss the various approaches to neonatal screening of galactosaemia in the light of experience in Massachusetts and South Australia. The use of cord blood can be expected to lead to diagnosis before babies with acute onset become ill, while the use of blood collected at five days for the Guthrie test avoids the collection of another routine sample for a relatively rare disorder. The result of red cell transferase assays of parents and siblings of our patients are discussed in relation to their implication for genetic counselling. The relevance of antenatal diagnosis to the prevention of possible intrauterine damage to an affected fetus is pointed out.

Human erythrocyte galactokinase and galactose-1-phosphate uridylyltransferase: a population survey

Erythrocyte (RBC) galactokinase (GALK) and galactose-1-phosphate uridylyl-transferase (GALT) activities were measured in a random sample of 1,700 (1.082 black and 618 white) pregnant women from the Philadelphia area to estimate the frequency of the genes GALKG and GALTG responsible for the two biochemically distinct forms of galactosemia. Blacks have significantly lower mean RBC GALK activities than whites (P less than .0005). The distribution of individual GALK activities for blacks differs from a normal distribution (X227=43.0, P less than .03) whereas that for whites does not (X224=25.5, P approximately equal to .30). These results are consistent with the thesis that reduced RBC GALK activity in blacks is due to the Philadelphia variant (GALKP), which is common in blacks and rare in whites. The frequency of heterozygotes (GALKG/GALKA, GALKG/GALKP) for GALK galactosemia observed in this sample is 1/340 for the total, 1/347 for blacks, and 1/309 for whites. The existence of the GALKP variant allele has been considered in this determination. However, because a method for distinguishing the GALKP and GALKG alleles became available only in the latter part of the study, the frequency of the GALK G allele in the black population may be underestimated. The mean RBC GALT activity for blacks is higher than that for whites, a difference that may be due to a higher frequency of the Duarte variant allele GALTD in whites. Heterozygotes (GALTG/GALTA) for GALT galactosemia were distinguished by family studies and starch gel electrophoresis from individuals who have half-normal RBC GALT activity due to the GALTD allele. The GALTG/GALTA frequency is 1/212 for the total, 1/217 for blacks, and 1/206 for whites. Of the 1,700 individuals surveyed three had atypically high RBC GALK activity, similar to that found in red blood cells of newborns.

Galactosemia: early structural changes in the liver

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