Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Viability of hetero- and homozygotes for beta-thalassemia was studied in two isolated populations born after 1950 in conditions of malaria absence. Pregnancy outcomes and probability to get 16 years old were compared in marriages, in which one or both parents were heterozygous for beta-thalassemia, and in marriages, with both parents being normal. The ratio of children with normal genotype and children heterozygous for beta-thalassemia in families, where one parent was heterozygous for beta-thalassemia. Preliminary conclusions are made on the basis of the data obtained. Viability of children in families where one parent is heterozygous for beta-thalassemia is found to decrease in the absence of selective factors (malaria) as compared with normal children. The highest viability decrease was observed in the progeny of those families where both parents were heterozygous beta-thalassemia. Elimination mainly takes place within the first year of life.
 ...
PMID:[Viability of beta-thalassemia hetero- and homozygotes in several populations of Central Asia]. 13 66

The prevalence of different haemoglobins and their interaction with malaria have been studied in Garki, Kano State, Nigeria. Sickle cell trait was present in 24% of newborn and 29% of those aged over five years. Hb.AC was present in 0.7%. Frequency of both haemoglobin variants was greater in Hausa than Fulani. Sickle cell anaemia was almost invariably fatal in early childhood. The distribution curve of percentage of Hb.S in sickle cell trait subjects was normal, and did not demonstrate any high frequency of a gene for alpha-thalassaemia. The presence of beta-thalassaemia minor could not be tested, but Hb.S/beta-thalassaemia was not detected. Hb.S gene frequency appears to have been maintained by a fitness in heterozygotes of 21% over normal homozygotes; increased fertility and high mutation rate did not make any apparent contribution. Hb.AS subjects had on average lower frequency and considerably lower densities of Plasmodium falciparum trophozoites than Hb.AA from the age of 30 to 59 weeks; density was less in sickle cell trait up to age three years in the dry season only. It is suggested that the survival advantage and hence the prevalence of sickle cell trait may be greatest in some hyperendemic areas and less where malaria transmission is extremely high or when it is high and unvaried.
 ...
PMID:Abnormal haemoglobins in the Sudan savanna of Nigeria. I. Prevalence of haemoglobins and relationships between sickle cell trait, malaria and survival. 31 11

Cape Town has a Greek community of about 5000, of whom approximately 75% originate from the island of Lesbos. In a survey of inherited haematological conditions in this population, 250 unrelated volunteers were investigated. The prevalence of heterozygous beta-thalassaemia was found to be 6.4%, with a gene frequency of 0.033. G6PD deficiency was detected in 10 males and it can be estimated that the prevalence in the male members of this population is 6.7%, with a gene frequency of 0.067. Hereditary spherocytosis was found in three respondents and this represents a prevalence of 1.2%, with a gene frequency of 0.006. One subject was heterozygous for the sickle cell trait (HbS) and another volunteer had haemoglobin Lepore, which had already been diagnosed in Greece. Our findings with respect to beta-thalassaemia and G6PD deficiency are similar to those reported from regions in Greece where malaria is not highly endemic.
 ...
PMID:Inherited anaemias in the Greek community of Cape Town. 46 97

The influence of malaria on HbA2 levels was investigated in two groups of children aged two to nine years from the Mano tribe of northern Liberia. One group, 174 children living in a town where there is malaria control, had a parasite rate of 6.5%, only a few having palpable spleens, but 282 children living in an area of intense malaria transmission had a parasite rate of 92%. All but one child in this group had enlarged spleens. However, the difference in proportions of elevated HbA2 values within the limits for beta-thalassaemia, 8% and 10.3% respectively, was not statistically significant (0.5 greater than P greater than 0.1). It was concluded that the influence of malaria on HbA2 levels is not significant and that this parameter is valid for detecting beta-thalassaemia trait in this population. Further, iron deficiency may be a more important factor than malaria to consider when assessing the results of HbA2 estimations.
 ...
PMID:Malaria and haemoglobin A2 levels in northern Liberia. 47 9

The influence of malaria on the hemoglobin A2 (Hb A2) level in humans was studied in a series of 94 imported cases in Belgium. Sixty-nine of the patients were natives of Western European countries, their results are reported separately since their origin and the results of their hematological examination made it unlikely that they carried the beta-thalassemia trait. The Hb A2 level of the 94 malaria patients (mean 2.76%; S.D. 0.51%) was not statistically different from that found in 60 healthy controls (mean 2.70%; S.D. 0.38%; P greater than 40). Likewise the level of the 65 Western European patients was not statistically different from that of the same controls (mean 2.81%; S.D. 0.42%; P greater than 0.10). There was also no significant difference between the level in patients infected with a particular species of Plasmodium and that of the controls. No correlation was found between the Hb A2 level and the intensity of the parasitemia or the concentration of total hemoglobin in the blood. These results are discussed in comparison with the divergent ones obtained by others and it is suggested that malaria has no significant influence on the results of surveys for the prevalence of beta-thalassemia in regions of malaria endemicity.
 ...
PMID:Hemoglobin A2 levels in malaria patients. 68 38

The occurrence of different types of hemoglobin variants in India has been well-documented in urban populations and in certain tribal areas. Beta-thalassaemia and hemoglobins D,E,H,S, and rare variants like Hb Lepore, have been found in varying percentages. There is a higher incidence of Hb E in the Eastern region and of Hb D in certain Northern populations. The association of Hb E with beta thalassaemia G6PD deficiency has been established. The relationship with other environmental factors, like malaria, is not yet clear.
 ...
PMID:Hemoglobin variants in India. 75 79

The present work reports a study of nine genetic polymorphic systems in the area of the Po Delta where malaria was endemic since the XIV century. Our data confirm some characteristics of this population already reported by other authors such as the high prevalence of thalassemia, the low prevalence of the rh (d) gene and the presence of G-6-PD deficiency. Among the other systems studied, i.e., AP, PGM1 ADA and AK, only AP frequencies of Po Delta population are significantly different from those of other continental Italian populations, the PC allele showing the lowest frequency so far observed.
 ...
PMID:A study of nine polymorphic systems in the population of the Po Delta. 96 38

Porotic hyperostosis was observed in 34 percent of 539 crania excavated from sites in Arizona and New Mexico. Common causes of this cranial pathology in the Old World (thalassemia, sickel cell anemia, and malargia) do not explain its occurrence in the American Southwest, as malaria and hemoglobinopathies are not known to have existed in the New World prior to European contact. Iron deficiency anemia which may also be assoicated with porotic hyperostosis occurs on a mass level only with hookworm infestation or nutritionally-related iron deficiency. Since hookworm infestation is rare in the American southwest and has not been reported in prehistoric southwestern American Indians, the hypothesis of nutritional anemia was examined. In canyon bottom sites where the diet was heavily dependent on maize, which is low in iron and also contains an inhibitor of iron absorption, significantly more crania had porotic hyperostosis than in sage plain sites, where the diet included ample animal protein rich in easily absorbable iron (p less than .001). Furthermore, canyon bottom children, who were more susceptible to iron deficiency anemia, had a higher incidence of porotic hyperostosis lesions than adults (p less than .0001).
 ...
PMID:The paleoepidemiology of porotic hyperostosis in the American Southwest: Radiological and ecological considerations. 110 84

A population survey in northern Liberia showed an average incidence of 9 percent of beta-thalassaemia trait. There was considerable tribal variation, the highest rates being mainly found in tribes having a low incidence of Hb S. A single example of deltabeta-thalassaemia trait was also found; the incidence of delta-chain variants was 1.8 percent. The effect of malaria on Hb A2 levels was investigated but appeared to be negligible. The problems of beta-thalassaemia and Hb S occurring in the same population are discussed. It is considered that, although made on a local sample, the results of this survey indicate a high incidence of beta-thalassaemia trait elsewhere in Liberia and that this is a suitable are for investigations of linkage at beta- and delta-chain loci. No conclusion is at present possible from the data on the presence of alpha-thalassaemia although 10 percent of neonates were found to have increased levels of Hb Barts.
 ...
PMID:Thalassaemia in northern Liberia. A survey in the Mount Nimba area. 112 Oct 21

The frequency of PC allele for acid phosphatase in fourteen Sardinian villages correlates positively with the altitude and negatively with past malarial morbidity and GdMed prevalence. The susceptibility towards hemolytic favism in Sardinian males with G6PD deficiency is dependent on the erythrocyte acid phosphatase and thalassemia phenotypes. Thalassemia trait exerts a protective action only in subjects carrying PA allele for acid phosphatase. The data suggest that the gradient for malaria morbidity directly or indirectly, through interactions with thalassemia and G6PD polymorphisms, mediated by the habit of eating Vecia faba, may have had a significant role in determining the heterogeneous distribution of acid phosphatase polymorphism in Sardinia. Besides malaria, other environmental factors related with altitude seem to have been very important in shaping the present pattern of distribution of both acid phosphatase and G6PD polymorphisms in Sardinia.
 ...
PMID:Red cell acid phosphatase: another polymorphism correlated with Malaria? 118 Mar 55


1 2 3 4 5 6 7 8 9 10 Next >>