A rare electrophoretic variant of superoxide dismutase (SOD) was found in one Filipino of 146 Filipinos, 1382 Malaysians and 816 Indonesians examined. The variant consists of two usual bands and two slower migrating bands similar to those reported earlier. Superoxide dismutase variants are common among people of certain localized regions in Europe, however, this is the first report of such a variant occurring in people of non-European origin.
944 adenosine deaminase phenotypings of Malay, Chinese, and Indian blood donors and newborns at Kuala Lumpur, Malaysia, yielded ADA1 gene frequency estimates of 0.885 for the Malays, 0.939 for the Chinese, and 0.853 for the Indians.
Plasma gamma-glutamyltranspeptidase (gamma-GT), glutathione peroxidase (GPx) and glutathione reductase (GR) activities were determined in normal and nasopharyngeal carcinoma (NPC) patients. No difference in enzyme activities was observed in the three major races of the Malaysian population, i.e. Malay, Chinese and Indian patients. However, plasma gamma-GT, erythrocyte glutathione S-transferase (GST) and GPx activities were significantly increased in all NPC patients, while GR activity remained unchanged. Patients with elevated plasma gamma-GT activities also had increased GST and GPx activities. Plasma gamma-GT and GPx activities were then found to be affected by treatment. Patients with plasma gamma-GT activity greater than 70 IU/l had very poor prognoses but patients with decreased gamma-GT activities were found to be in remission.
Biochemical characteristics of one non-deficient fast G6PD variant (GdSingapore) and six different deficient variants (three new, two Mahidol, one each of Indonesian and Mediterranean) were studied among the Malays of Singapore. The GdSingapore variant had normal enzyme activity (82%) and fast electrophoretic mobilities (140% in TEB buffer, 160% in phosphate and 140% in Tris-HCl buffer systems respectively). This variant is further characterized by normal Km for G6P; utilization of analogues (Gal6P, 2dG6P; dAmNADP), heat stability and pH optimum. The other six deficient G6PD variants had normal electrophoretic mobility in TEB buffer with enzyme activities ranging from 1 to 12% of GdB+. The biochemical characteristics identity them to be 2 Mahidol, 1 Indonesian and 1 Mediterranean variants and three new deficient variants.
Cord blood from 8,975 babies delivered in Hospital Sultanah Aminah Johor Bahru over a period of eight months (1st August 1985 to 31st March 1986) were screened for G6PD deficiency. The overall incidence was 4.5% in Chinese, 3.5% in Malays and 1.5% in Indian babies. One hundred of these babies were observed in the nursery for seven days and their daily serum bilirubin recorded. The serum bilirubin peaked at 96 hours to a value of 12mg%. None of the babies in the nursery developed a serum bilirubin level of more than 15mg%. Six of the babies with G6PD deficiency that were sent home were readmitted with hyperbilirubinaemia that needed exchange transfusion.
A study of glutathione reductase (GR) activity and its stimulation by flavin adenine dinucleotide (FAD) in erythrocytes of Malaysian newborns and adults of different racial groups showed that GR stimulation by FAD was greater than 20% in 50% of 866 newborns (57% of Malays, 55% of Indians and 41% of Chinese) and 54% of 274 adults (46% of Malays, 65% of Indians and 45% of Chinese). There was a significant negative correlation between GR activity and percentage FAD stimulation in both newborns and adults in all racial groups. Low GR activity and a high percentage FAD stimulation were more prevalent among parents of newborns with low GR activity than among parents of newborns with higher GR activity. Administration of riboflavin to mothers with low GR activity resulted in increased GR activity and a decreased percentage of FAD stimulation. None of the individuals examined had clear clinical manifestations of riboflavin deficiency. It is concluded that subclinical riboflavin deficiency leading to low GR activity is prevalent in Malaysia among adults and newborns, especially among Malays and Indians.
The distribution of red cell phosphoglucomutase (PGM) subtypes was determined by starch-gel electrophoresis and isoelectric focusing in a group of 2,484 unrelated individuals from ten Mongoloid populations of East Asia. The sample comprised 998 Chinese from various localities--Singapore, 325; Malaysia, 270; Taiwan, 276; Hong Kong, 67; Fouzhou, 60--as well as 342 Koreans; 252 Filipinos; 529 Thais; 336 Malays, and 27 Indonesians. Altogether 15 phenotypes controlled by four common and five rare alleles at the PGM1 locus were observed in these populations. The frequency of the most frequent allele (PGM1+) varied from 0.56 to 0.74, with the highest frequency observed in the Singapore Chinese and the lowest in the Malays. Within the Chinese from different localities a significant degree of heterogeneity was observed at the PGM1 locus. The rare allele (PGM17)6 was observed only among the Chinese, Thais, and Malays, while the PGM1 was lacking in the Filipinos. A new allele with ahigh pI (6.5) was observed in a low frequency in all the populations but the Malays.
The Land and Sea Dayaks of Sarawak were surveyed for several erythrocyte enzymes. The gene frequency of 6PGDC in 132 Land Dayaks and 127 Sea Dayaks were 0.045 and 0.047, respectively. The gene frequency of PGM1-1 IN 285 Land Dayks and 240 Sea Dayaks were 0.716 and 0.779, respectively. The ADA2 gene frequency in 283 Land Dayaks and 188 Sea Dayaks were 0.154 and 0.090. ADA 5-1 was found once in the Land Dayaks and once in the Sea Dayaks. AK 2-1 was found once in 221 Sea Dayaks but not in any of 270 Land Dayaks. No PHI, LDH or CA variants were found among the Land or Sea Dayaks.