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Red blood cell (RBC) membrane disorders represent a significant category of hereditary hemolytic anemia; however, information from Southeast Asia is limited. We established a national registry aiming to characterize RBC membrane disorders and their molecular features in Thailand. A total of 100 patients (99 kindreds) diagnosed with RBC membrane disorders between 2011 and 2020 from seven university hospitals were enrolled. The most prevalent disorders observed were hereditary elliptocytosis (HE; n=33), hereditary pyropoikilocytosis (HPP; n=28), hereditary spherocytosis (HS; n=19), Southeast Asian ovalocytosis (SAO; n=10 of 9 kindreds), and two cases of homozygous SAO. The remaining cases were grouped as unclassified membrane disorder. Seventy-six patients (76%) were molecularly confirmed by PCR, direct DNA sequencing, or hi-throughput sequencing. The primary causative gene for HE and HPP was SPTB, accounting for 28 out of 29 studied alleles for HE and 56 of 56 studied alleles for HPP. In the case of HS, dominant sporadic mutations in the ANK1 gene (n=4) and SPTB gene (n=3) were identified as the underlying cause. Notably, the four most common variants causing HE and HPP were SPTB Providence (c.6055 T>C), SPTB Buffalo (c.6074 T>G), SPTB Chiang Mai (c.6224 A>G), and SPTB c.6171__82delins TGCCCAGCT. These recurrent SPTB mutations accounted for 79 out of 84 mutated SPTB alleles (94%). In summary, HE and hereditary HPP associated with recurrent SPTB mutations are the predominant types of RBC membrane disorders observed in Thailand. These findings have significant implications for the clinical management and future research of RBC membrane disorders in the region., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.) more...

Objectives: Southeast Asian ovalocytosis (SAO) is an inherited red blood cell (RBC) membrane disorder, whereas hemoglobinopathies are inherited globin gene disorders. In an area where both diseases are prevalent, the interaction between them resulting in variable hematologic parameters can be encountered. However, little is known about the genetic interaction of SAO and thalassemia. We investigated the prevalence of SAO and hemoglobinopathy genotypes among newborns in southern Thailand., Patients and Methods: This study was carried out on 297 newborns recruited consecutively at Naradhiwas Rajanagarindra Hospital in the south of Thailand. The SAO was identified on blood smear examination and polymerase chain reaction analysis. Thalassemia genotypes were defined. Hematologic parameters and hemoglobin (Hb) profiles were recorded and analyzed., Results: Among 297 newborns, 15 (5.1%) carried SAO, whereas 70 (23.6%) had thalassemia with 15 different thalassemia genotypes. Abnormal Hb including Hb C, Hb Q-Thailand, and Hb D-Punjab were observed in 5 newborns. It was found in the nonthalassemic newborns that RBC count, Hb, and hematocrit of the nonthalassemic newborns with SAO were significantly lower than those without SAO. The same finding was also observed in the thalassemic newborns; RBC count, Hb, and hematocrit of the thalassemic newborns with SAO were significantly lower than those without SAO. However, the mean corpuscular volume, mean corpuscular Hb, and RBC distribution width of the SAO-newborns were significantly higher., Conclusions: Both SAO and hemoglobinopathy genotypes are common in southern Thailand. One should take this into consideration when evaluating neonatal anemia and other hematologic abnormalities. Identification of both genetic defects and long-term monitoring on the clinical outcome of this genetic interaction should be essential to understand the pathogenesis of these common genetic disorders in the region., Competing Interests: The authors declare no conflict of interest., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.) more...

We cared for a neonate who had problematic hyperbilirubinemia born into a family where nine first-degree relatives had hereditary elliptocytosis (HE). As neonates, the nine relatives did not have any significant jaundice or anemia that was recognizable. Blood films on the proband suggested a diagnosis of pyropoikilocytosis. Analysis of the α-spectrin gene (SPTA1) in the proband revealed two previously reported low-frequency heterozygous polymorphisms of unknown clinical significance and the α(LELY) allele. In addition, a novel heterozygous mutation was identified in exon 2 of the β-spectrin gene SPTB. No mutations were identified in ANK1 (ankyrin-1), SLC4A1 (band 3), EPB41 (band 4.1), or EPB42 (band 4.2)., (© 2013 S. Karger AG, Basel.) more...

Background: The erythrocyte polymorphism, Southeast Asian ovalocytosis (SAO) (which results from a 27-base pair deletion in the erythrocyte band 3 gene, SLC4A1Δ27) protects against cerebral malaria caused by Plasmodium falciparum; however, it is unknown whether this polymorphism also protects against P. vivax infection and disease., Methods and Findings: The association between SAO and P. vivax infection was examined through genotyping of 1,975 children enrolled in three independent epidemiological studies conducted in the Madang area of Papua New Guinea. SAO was associated with a statistically significant 46% reduction in the incidence of clinical P. vivax episodes (adjusted incidence rate ratio [IRR] = 0.54, 95% CI 0.40-0.72, p<0.0001) in a cohort of infants aged 3-21 months and a significant 52% reduction in P. vivax (blood-stage) reinfection diagnosed by PCR (95% CI 22-71, p = 0.003) and 55% by light microscopy (95% CI 13-77, p = 0.014), respectively, in a cohort of children aged 5-14 years. SAO was also associated with a reduction in risk of P. vivax parasitaemia in children 3-21 months (1,111/µl versus 636/µl, p = 0.011) and prevalence of P. vivax infections in children 15-21 months (odds ratio [OR] = 0.39, 95% CI 0.23-0.67, p = 0.001). In a case-control study of children aged 0.5-10 years, no child with SAO was found among 27 cases with severe P. vivax or mixed P. falciparum/P. vivax malaria (OR = 0, 95% CI 0-1.56, p = 0.11). SAO was associated with protection against severe P. falciparum malaria (OR = 0.38, 95% CI 0.15-0.87, p = 0.014) but no effect was seen on either the risk of acquiring blood-stage infections or uncomplicated episodes with P. falciparum. Although Duffy antigen receptor expression and function were not affected on SAO erythrocytes compared to non-SAO children, high level (>90% binding inhibition) P. vivax Duffy binding protein-specific binding inhibitory antibodies were observed significantly more often in sera from SAO than non-SAO children (SAO, 22.2%; non-SAO, 6.7%; p = 0.008)., Conclusions: In three independent studies, we observed strong associations between SAO and protection against P. vivax malaria by a mechanism that is independent of the Duffy antigen. P. vivax malaria may have contributed to shaping the unique host genetic adaptations to malaria in Asian and Oceanic populations. Please see later in the article for the Editors' Summary. more...

Southeast Asian ovalocytosis (SAO), α(+)-thalassemia, and low expression of complement receptor 1 (CR1) have been associated with protection against severe Plasmodium falciparum malaria. In a cohort of children 5-14 years of age the effect of α(+)-thalassemia, SAO (SLC4A1Δ27), CR1 polymorphisms, and Gerbich negativity (GYPCΔex3) on risk of P. falciparum infections and uncomplicated illness were evaluated. The risk of acquiring polymerase chain reaction (PCR)-diagnosed P. falciparum infections was significantly lower for α(+)-thalassemia heterozygotes (hazard ratio [HR]: 0.56) and homozygotes (HR: 0.51) than wild-type children. No such differences were seen in light of microscopy diagnosed infections (P = 0.71) or were α(+)-thalassemia genotypes associated with a reduced risk of uncomplicated P. falciparum malaria. No significant associations between the risk of P. falciparum infection or illness were observed for any of the other red blood cell polymorphisms (P > 0.2). This suggests that these polymorphisms are not associated with significant protection against P. falciparum blood-stage infection or uncomplicated malaria in school-aged children. more...

Malaria during pregnancy, which is characterized by the accumulation of infected erythrocytes in the placenta, often has severe consequences for the mother and newborn. We assessed the effect of the genetic trait South-East Asian ovalocytosis (SAO) on placental malaria in women from Papua New Guinea. In children, this trait confers protection against cerebral malaria, but not against mild malaria disease, malaria parasitemia, or severe malaria anemia. Using a case-control approach, we found that SAO women suffer from placental malaria, and SAO-infected erythrocytes can sequester in the placenta, but heavy placental infections tended to be less common in SAO than in control pregnant women. Reduced prevalence and severity of placental infection associated with SAO were observed only for primigravid women, who are the group at highest risk of suffering from severe manifestations of placental malaria. Furthermore, we found that the prevalence of the SAO trait was lower among pregnant women than among non-pregnant controls. more...

The native population of Bahrain has a high prevalence of hemoglobinopathies and G6PD deficiency, probably as a result of past malarial endemism. We used the Biorad-Variant hemoglobin testing system for primary screening of hemoglobinopathies in 20,000 individuals. Hemoglobin abnormalities were detected in 7,206 (36.3%) cases. more...

In the Madagascar Highlands, 0.76% of children from 168 random primary schools, and 19 of 150 families from 3 villages, had oval-shaped erythrocytes. Most harboured the deletion in the band 3 gene characteristic of South-East Asian ovalocytosis. This genetic trait supports the Indonesian origin of the Madagascar settlement. more...

This study describes the characteristic features of the incidence of hereditary red cell membrane disorders in the Japanese population based on studies of 1014 cases of these disorders from 605 kindred. Among them, there were 581 cases of hereditary spherocytosis (HS) from 303 kindred, 137 cases of hereditary elliptocytosis (HE) from 68 kindred, 104 cases of hereditary stomatocytosis (HSt) from 64 kindred, and 34 cases of protein 4.2 (P4.2) anomalies from 20 kindred, and 41 cases of membrane lipid anomalies from 27 kindred. In HS patients, eleven mutations of the band 3 (B3) gene, 15 mutations of the ankyrin gene, and three mutations of the protein 4.2 (P4.2) gene, which are pathognomonic for this disorder, were identified. Most of these mutations had not been reported and, with few exceptions, were specific to the Japanese population. P4.2 abnormalities also appear to be unique to the Japanese population. The biochemical and biophysical functions of P4.2 are associated with stabilization of the cytoskeletal network by anchoring it to integral proteins (especially B3). Biochemical and genetic analyses of the HE patients revealed one family with an α-spectrin (Sp) anomaly (HE [α(1/74)]) and three kindred with β-spectrin abnormalities (β-Sp Yamagata, β-Sp Tokyo, and β-Sp Nagoya) due to abnormal splicings of the β-Sp gene. On the basis of these observations, the relationship between the genotypes and phenotypes is reviewed. In addition, the morphogenesis of red cell membranes with regard to the sequential expression of these membrane proteins was also discussed. Finally, from the standpoint of gene expression, a possible role of gene methylation as an epigenetic control was proposed. more...

Screening for a 27-bp deletion in the band 3 protein gene that causes Southeast Asian/Melanesian ovalocytosis (SAO) was carried out using the PCR method among 15 Southeast Asian populations of Thailand (Akha, Hmong, Isaan, Red Karen, White Karen, Black Lahu, Lisu, Manni, Shan, and central Thais) and Indonesia (Bugis, Dayak, Javanese, Madurian, and Toraja). Individuals with the 27-bp deletion were identified only in the Bugis of southern Sulawesi, the Dayak of southern Borneo, and Javanese of central Java. The gene frequency of the 27-bp deletion in the general population was rather low: 0.012 and 0.013 in the Dayak and the Bugis, respectively. This restricted ethnic and geographic distribution of the 27-bp deletion suggests (1) local differentiation in the prevalence of this deletion in a given ethnic group and (2) the presence of molecular heterogeneity of SAO. more...

Hereditary elliptocytosis (HE) is a group of hemolytic anemias characterized by the presence of elliptical erythrocytes. The underlying alterations lie in the proteins of the membrane skeleton. Defects of the alphaI domain of spectrin have been defined based on a decrease in the normal 80-kD alphaI domain and a concomitant increase in one or more lower molecular weight peptides. We have studied three Brazilian kindreds with black ancestry, who presented mild common spalphaI/50 HE. Our aim was to determine the molecular alteration responsible for the spalphaI/50 HE observed in these three kindreds and to evaluate the presence and influence of allele alphaLELY in the expression of this type of HE. In order to establish the molecular defect, exons 5, 6 and 11 were amplified and submitted to a nonradioactive single strand conformation polymorphism protocol. An identical band shift in exon 6 was observed in all 3 patients and their affected relatives. Direct sequencing of the amplification products of exon 6 showed the same molecular defect in all patients: a T-->C substitution, responsible for the L260P mutation. Allele alphaLELY, detected by PCR and restriction enzyme digestion, was present in the heterozygous form in the three propositi and was associated in trans with the elliptocytogenic mutation. Blood smears of the patients with HE and alphaLELY in trans showed pronounced elliptocytosis, poikilocytosis and a few small red cell fragments, whereas the blood smears of their relatives, who had HE without allele alphaLELY, showed mild common HE with a predominance of ovalocytes and the absence of poikilocytes. We conclude that allele alphaLELY does not lead to the worsening of clinical conditions when associated in trans with mild HE, but can be easily distinguished by a blood smear analysis. The predominance of the L260P mutation in the kindreds studied could be related to the colonization of Brazil during the slave trade by Africans from the Benin-Togo area, where this mutation is particularly common. more...

South-east Asian ovalocytosis status was determined in 1629 individuals originating from 12 different geographical areas of Papua New Guinea, representing different ethnic groups and degrees of malaria endemicity. This was achieved by using polymerase chain reaction amplification to demonstrate a 27 base pair deletion in the erythrocyte band 3 (AE1) gene. By using this method, the prevalence of erythrocyte band 3 gene deletion was determined to range from zero in both the lowland inland area of Wosera, East Sepik Province and the highland region of Goroka, Eastern Highlands Province to 35% on the north coast of Madang Province. In general, the prevalence correlated well with altitude, being highest on the coast where malaria transmission is high, intermediate in the lowlands, and lowest in the non-malarious highlands. However, Wosera, a lowland area in the Sepik River Plains, which is hyperendemic for malaria, was an exception in that no ovalocytosis was detected. These results largely confirm the prevalence rates that have been reported in the past using microscopy. In keeping with the autosomal dominant mode of inheritance, the male:female ratio was 1.02 and no homozygote was detected, indicating that homozygosity for the ovalocytosis band 3 gene deletion is lethal. more...

The authors report the importance of not only all over the world but also in Portugal and, particularly, in Dona Estefânia Hospital. Some considerations are made about the usefulness of molecular biology methods in prenatal diagnosis. With this tool can also be do the origins and migrations of populations, which contributes to the knowledge of aspects of our history. Finally, they present consensual attitudes which should adopt regarding these chronic diseases, with special emphasis to the prophylactic aspects. more...

The malaria parasite rates and densities were compared in 79 ovalocytic-normocytic pairs of Malayan Aborigines matched for age, sex, proximity of residence to each other, and use of bed nets when sleeping in their jungle settlement in central Peninsular Malaysia. Malaria infection was determined from thick and thin Giemsa-stained blood films collected monthly for a period of six months. Blood films from ovalocytic individuals were found to be positive for malaria less often than in persons with normal red blood cells (P less than 0.05). Malaria infections per 100 person-months at risk were 9.7 in the ovalocytic group compared with 15.19 in the normocytic group. Among individuals parasitemic at any time, heavy infections (greater than or equal to 10,000 parasites/mm3 of blood) with Plasmodium falciparum, P. vivax, and P. malariae were encountered only in normocytic subjects, which comprised approximately 12.5% of the malaria-positive individuals in this group. In an earlier survey of 629 settlers that identified subjects for the above study, the prevalence of ovalocytosis was found to increase significantly with age. The above field observations support the view that ovalocytic individuals might have a survival advantage in the face of malaria. Consideration of the ovalocytic factor is indicated in future evaluations of malaria control measures in areas where ovalocytosis is prevalent. more...

alpha I/65 Hereditary elliptocytosis (HE) is due to the duplication of TTG codon 154 (leucine) of alpha-spectrin and is associated with a constant haplotype. It was encountered exclusively in African and American Blacks, and in North Africans. We assumed that it diffused from the Benin-Togo area to Northern Africa. We now report two South Italian families with alpha I/65 HE. The phenotype fully conformed to previous descriptions. The mode of transmission was dominant; however, the manifestations were more pronounced when the common, low expression level alpha V/41 allele occurred in trans to the alpha I/65 allele, also conforming to previous records. The mutation underlying alpha I/65 HE turned out to be, again, the duplication of TTG codon 154 and the associated haplotype was the same as that encountered previously (+-+; XbaI, PvuII, MspI). Thus, the alpha I/65 allele found in Italy must have been introduced from North Africa across the Sicilian channel and would ultimately have originated from the Benin-Togo area. It would witness the same migratory stream as that followed by the Benin type haemoglobin S allele, which is also present in Southern Italy. more...

Red cell analysis using the laser technique was done on erythrocytes from 11 cases of hereditary ovalocytosis (HV) and one case of hereditary spherocytosis (HS). Heterogeneity in red cell volume measured as red cell distribution width (RDW) and heterogeneity of hemoglobin concentration in the red cells as measured by hemoglobin concentration distribution width (HDW) were analyzed. All of the studied cases showed abnormal increase in both RDW and HDW. The patient with HS had decreased MCV 77.4 fL (normal range = 80-99 fL). The HS patient had microcytes 14.7 per cent with markedly increased RDW 22.3 per cent (normal range = 11.5-14.5%). Increased hemoglobin concentration was demonstrated in HS red cells as shown by increased CHCM 39.2 g/dl (normal range = 33-37) with 5.86 g/dl of HDW (normal range = 2.2-3.3 g/dl). The HV patients had slightly decreased cell volume, MCV = 84.1 +/- 11.8 fL, with 9.2 +/- 10.1 per cent microcytes and 17.5 +/- 5.7 per cent RDW. Decreased hemoglobin concentration was shown in HV red cells as shown by decreased CHCM (31.7 +/- 1.9 g/dl) with slightly increased HDW (3.3 +/- 0.9 g/dl). The HV patients had increased per cent hypochromic red cells (14.8 +/- 18.6%). The ovalocytic red cells in HV patients had obviously reduced hemoglobin concentration compared to the spherical red cells of HS patients. more...

4.1(-) hereditary elliptocytosis (HE) is a variety of elliptocytosis resulting from the reduction (heterozygosity) or the absence (homozygosity) of protein 4.1. It is nearly always encountered in its heterozygous form. It has been found among Caucasians and North Africans in a sporadic fashion. We report the study on nine family cases of 4.1(-) HE. They were recruited independently (to the exclusion of any other variety of HE) in a limited area around the city of Annecy (French Northern Alps). The mode of genetic transmission, as well as the clinical, morphologic, and protein phenotypes fully conformed to the classical description. Western blots ruled out the existence of any protein 4.1 species of abnormal size. No obvious DNA rearrangement was detectable in any of the nine families with three 4.1 cDNA probes covering the entire coding sequence and part of the flanking 5' and 3' untranslated sequences. On the basis of five polymorphic sites (Bgl II, 2; Pvu II, 3), we found five different haplotypes in normal members of the 4.1(-) families. 4.1(-) HE was associated with the most common haplotype in all the propositi. 4.1 mRNA was studied in four families. Dot-blot hybridization experiments and Northern blots failed to show any detectable change in three families. On the other hand, they showed a 2-kb deletion in the 4.1(-) messenger RNA 5'-moiety in one family. These findings emphasize the heterogeneity of 4.1(-) HE at the molecular level. more...

Blood samples were drawn from 456 healthy children, 6-10 years old, to explore the prevalences of haemoglobinopathies in Northern Jordan Valley. The children were selected by the multi-stage random sampling technique. Complete blood count, haemoglobin electrophoresis and haemoglobin A2 (HbA2) estimations were carried out on all the samples. The prevalences of beta-thalassaemia minor, alpha-thalassaemia trait, sickle cell trait, and hereditary elliptocytosis were 15(3.3%), 16(3.5%), 2(0.44%) and 4(0.89%), respectively. more...

A survey of abnormal haemoglobins and hereditary ovalocytosis was carried out among 629 Malays of Minangkabau descent in the Ulu Jempul District of Kuala Pilah, in the state of Negri Sembilan in West Malaysia.. Several abnormal haemoglobins were found with the following frequencies: Hb E 5.25%, Hb CoSp 2.38%, Hb A2 indonesia 0.80%, a fast moving Hb with a Mobility between A and Bart's 0.64% and Hb Q 0.16%. Hereditary ovalocytosis was found in 13.2% of these people. None of the persons with hereditary ovalocytosis had any evidence of haemolysis. more...

We report the distribution of two genetic traits, glucose-6-phosphate dehydrogenase (G-6-PD) deficiency and hereditary ovalocytosis (HO) in a number of populations living in the Ok Tedi impact region of Papua New Guinea. Significant interpopulation heterogeneity in the distributions of G-6-PD deficiency and HO was observed. The highlands populations of the region did not show any G-6-PD deficiency, but in the highlands fringe and lowland populations the trait has achieved polymorphic frequencies. Hereditary ovalocytosis is significantly more common in the region and is present in all the populations studied, including those in the highland valleys. Distribution patterns of the two genetic markers correspond well with the pattern of malaria endemicity in the region, providing support for the hypothesis that relates the distribution of these polymorphisms to that of malaria. more...

In 50 Kerema or Kairuku individuals of the Papuan Gulf Area, the amount of beta thalassaemia as indicated by the finding of a raised level of Hb A2 was found to be 6%, and of hereditary ovalocytosis 16%. There was one example of both conditions occurring together. No haemoglobin abnormalities apart from raised Hb A2 level were found. more...

The authors report 6 cases of hereditary elliptocytosis during a screening in one thousand (1,000) black persons. The analysis of these cases of elliptocytosis allow to draw the following conclusions: the frequency of the hereditary elliptocytosis varies between 0.6 to 1 per cent in Ivory Coast, the functional and structural analysis of spectrin show a high global frequency of the elliptocytosis of Model I in relation with an abnormally of alpha I domain of spectrin, all the cases detected don't give any clinical trouble. more...

Ovalocytosis, an hereditary condition in which most erythrocytes are oval in shape, is a polymorphism that occurs in up to 20% or more of the population in Papua New Guinea and Malaysia. Due to the geographical correlation of the trait with endemic malaria, the possibility of a selective advantage in resistance to malaria has been raised. In a study of 202 individuals with greater than or equal to 50% oval red cells matched by age, sex and village of residence with controls having less than or equal to 30% oval cells, ovalocytic subjects had blood films negative for Plasmodium vivax (P = 0.009), for P. falciparum (P = 0.044), and for all species of malaria parasites (P = 0.013), more often than controls. Among individuals parasitaemic at any time there were no clear differences in density of parasitaemia. However, in children 2 to 4 years old, parasite densities of both species were lower in ovalocytic subjects than in controls (0.01 less than P less than 0.025). The differential susceptibility to malaria infection suggested by this study has implications for the evaluation of interventions, including possible future vaccine field trials, in populations where high-frequency ovalocytosis is present. more...

A survey of abnormal hemoglobins, G6PD deficiency and hereditary ovalocytosis was carried out among the Dayaks of Sarawak. The only abnormal hemoglobin found was Hb Co Sp, which occurred in 0.35% of the Land Dayaks and 0.83% of the Sea Dayaks. G6PD deficiency occurred in 5.3% of the male Land Dayaks and 5.0% of the male Sea Dayaks; no electrophoretic variant of G6PD was found in any of the 285 Land Dayaks and 240 Sea Dayaks examined. Hereditary ovalocytosis was found in 12.7% of the Land Dayaks and 9.0% of the Sea Dayaks. more...

Hereditary ovalocytosis in Papua New Guinea is restricted to areas of endemic malaria and may confer increased resistance to the disease. The incidence of malaria was investigated in 1616 Melanesiams of known red cell morphology and severity of infection determined in a smaller subsample. Ovalocytics tended to be more resistant to severe malarial infections than normocytics. The ratio of parasitaemia in 112 ovalocytics compared with 741 normocytic children was 1.05 for P. falciparum; 0.90 for P. vivax; 0.54 for P. malariae, and 0.91 for infection with any species. The difficulties in conclusively demonstrating any selective advantage of the condition are discussed. more...

Hereditary Elliptocytosis (HE) is a hemolytic disorder inherited as autosomal-dominant trait and characterized by elliptically shaped erythrocytes. Preliminary studies in France have showed a high proportion of HE patients of black extraction (West Africa and Antilles). In order to confirm this prevalence, we made a systematic search for HE in West Africa: Benin, Burkina Faso, Ivory Coast, Togo. The diagnosis of elliptocytosis was established by the observation of a high percentage (greater than 70%) of characteristic regular and symmetric elliptic red cells after fixation in 0.3% glutaraldehyde saline buffer. The diagnosis of HE was confirmed by cytological studies of related members and/or the discovery of a well defined molecular variant of spectrin, the main protein of erythrocyte membrane skeleton. We found: in Abidjan centre 6 HE out of 1,000 subjects representative of main ethnic groups; in Lome Centre 6 cases out of 750 subjects originated from the South or Central areas of Togo; in Cotonou Centre 5 cases out of 1,000 subjects originated from the South area of Benin; in Bobo Dioulasso centre 6 HE out of 700 subjects. From this multicentre studies HE appears roughly 10 times more frequent in West Africa than in Europe or USA where incidence was estimated at between 2.5 and 5 cases per 10,000. Tryptic digestion of spectrin revealed that: 10 patients from different ethnic groups have the most frequent variant found in our laboratory (21 kindreds) and named spectrin alpha I/65. Five cases originated from limited areas in the South of Benin and Togo and related to closed ethnic groups have the variant Sp alpha I/46. more...

A distinctive type of hereditary ovalocytosis has been found in Papua New Guinea and a few areas of Southeast Asia. Its main features include a high incidence among tropical lowland dwellers, autosomal recessive inheritance, specific depression of a number of red cell antigens, a characteristic morphology in blood films, and an effect on the erythrocyte sedimentation rate. Speculation has occurred as to whether the high incidence of ovalocytosis in malarious areas may be related to a selective advantage possessed by ovalocytics with regard to severe malaria. Preliminary data tend to support this hypothesis, but the evidence is not conclusive and much further work is needed. more...