Search

alpha-Galactosidase and beta-galactosidase activities have been determined in leukocyte preparations from 100 randomly selected Chinese adults. For alpha-galactosidase, two groups with low activities were identified: group I consisted of 3 females having activities below 40% of normal, and group II consisted of 5 males and 1 female with activities about 60% of normal. Family studies suggested that these low alpha-galactosidase activities are genetically determined. Only 1 individual was found to have about 50% of normal beta-galactosidase activity; presumably he is a carrier for beta-galactosidase deficiency (GM1 gangliosidosis).

Somatic cell hybrids between mouse and human cells containing two different reciprocal translocations involving human chromosome 1, 46, X, t(l;X)(ql2;q26) and 47, XX, + 21, t(l;17)(p32;pl3), were studied for the expression of human uridine diphosphate galactose 4-epimerase (UDPGal 4-epimerase, E.C. 5.1.3.2) by starch-gel electrophoresis. Analysis of the hybrid clones for the expression of the enzyme and the presence of the translocation chromosome 1 has permitted the assignment of the gene for human UDPGal 4-epimerase to the pter→p32 region of chromosome 1.

£A standard G-band karyotype is proposed for the genus Peromyscus. G-banded chromosomes of Peromyscus boylii glasselli (NF = 56), numbered and arranged according to euchromatic lengths, serve as the standard. It is suggested that rearrangements of the standard pattern which occur in other species of Peromyscus be described using the general methods of the Paris Conference (1971).

A low activity galactose-1-phosphate uridyl transferase (GALT) variant in siblings has been demonstrated by biochemical studies on erythrocytes and cultured skin fibroblasts. The index case was identified during routine Beutler screening in the newborn period but was not clinically studied until 1/2 mth, when the child presented as normal in all respects. However, early biochemical studies showed a marked reduction in GALT, increased plasma and urinary galactose and substantial amounts of RBC galactose-1-phosphate. Extended studies of this child and a younger affected sibling have shown: (1) The RBC’s contain ‘real’ but reduced GALT; (2) The cultured fibroblasts contain ‘real’ but reduced GALT; (3) On gel electrophoresis, the RBC GALT has similar mobility to the normal enzyme; (4) The RBC galactose-1-phosphate response to an oral galactose tolerance test is similar to that for a patient heterozygous for both Duarte and classical galactosaemia (DG); (5) During dietary restriction of galactose intake the RBC galactose-1-phosphate and the urinary excretion of galactitol is significantly lower than found in those homozygous for ‘classical galactosaemia’ (GG) under treatment; (6) The GALT in haemolysate appears to be more heat labile. Our present conclusion is that these children are heterozygotes for the classical galactosaemia gene and a ‘new variant’ (GG*).