Iron state in alpha and beta thalassaemia trait

COMBINED CENTRAL RETINAL VASCULAR OCCLUSION AS THE PRESENTING FEATURE IN β-THALASSEMIA WITH IRON DEFICIENCY ANEMIA

PURPOSE

To report a case of β-thalassemia trait with iron deficiency anemia presenting as a combined central retinal vein and artery occlusion.

METHODS

Case report. A 22-year-old woman presented with sudden-onset blurry vision in the left eye of 3-day duration.

RESULTS

Best-corrected visual acuity was 20/20 and 20/1000 in right and left eyes, respectively. Fundus examination of the left eye revealed optic disk edema, macular whitening with a cherry-red spot, markedly dilated and tortuous retinal veins, and hemorrhages both around the disk and extending into the macula and the periphery. Fundus fluorescein angiography showed delayed filling of retinal vasculature, dilated and tortuous retinal veins, and blocked fluorescence around and beyond the optic disk. Optical coherence tomography scan at presentation showed hyperreflective inner retinal layers with neurosensory detachment. Optical coherence tomography angiography showed that the vessel densities of superficial and deep capillary plexus were remarkably reduced. A diagnosis of β-thalassemia trait combined with iron deficiency anemia was made after hematologic workup. The patient was treated with a course of oral iron supplements, vasodilator (compound Xueshuantong), inhalation of a mixture of 5% carbon dioxide and 95% oxygen, and a nutritional agent (compound anisoine). Six months later, her visual acuity improved to 20/60 in the left eye with complete resolution of all clinical signs.

CONCLUSION

Combined central retinal vein and artery occlusion is a rare emergency leading to acute vision loss and can manifest in patients with β-thalassemia trait with iron deficiency anemia. Prompt diagnosis and early management is important to treat underlying systemic disorders and to prevent occurrence of a similar episode in fellow eye.

The Prevalence of α-Thalassemia and Its Relation to Plasmodium falciparum Infection in Patients Presenting to Clinics in Two Distinct Ecological Zones in Ghana

Thalassemia and sickle cell disease constitute the most monogenic hemoglobin (Hb) disorders worldwide. Clinical symptoms of α(+)-thalassemia (α(+)-thal) are related to inadequate Hb production and accumulation of β- and/or γ-globin subunits. The association of thalassemia with malaria remains contentious, though from its distribution it appears to have offered some protection against the disease. Data on the prevalence of thalassemia in Ghana and its link with malaria is scanty and restricted. It was an objective of this cross-sectional study to determine the prevalence of thalassemia in areas representing two of Ghana's distinct ecological zones. The relationship between thalassemia and Plasmodium falciparium (P. falciparum) infection was also ascertained. Overall, 277 patients presenting to health facilities in the study areas were recruited to participate. Tests were carried out to determine the presence of α(+)-thal, sickle cell and malaria parasites in the blood samples of participants. The outcome of this study showed an α(+)-thal frequency of 19.9% for heterozygotes (-α/αα) and 6.8% for homozygotes (-α/-α). Plasmodium falciparum was detected in 17.7% of the overall study population and 14.9% in those with α(+)-thal. No association was observed between those with α(+)-thal and the study sites (p > 0.05). A test of the Hardy-Weinberg law yielded no significant difference (p < 0.001). Findings from this study suggest a modest distribution of α(+)-thal in Ghana with no bias to the ecological zones. Although the prevalence and parasite density were relatively low in those with the disorder, no association was found between them.

Maternal and perinatal outcomes amongst haemoglobinopathy carriers: a systematic review

With the introduction of screening programmes for haemoglobinopathies (HbP), more women will be aware of their HbP status. The genetic risk for women who are carriers of HbP is well known. However, midwives and obstetricians need to know whether there are other risks involved in the pregnancies of women who are carriers of HbP. The objective of this study was to investigate the hypothesis that being a carrier of HbP has no consequences for the health of pregnant women and the outcome of their pregnancies. A systematic search was carried out until August 2008 in the Cochrane Library, Medline, EMBASE and CINAHL databases. All references were inspected to identify further studies. The authors of key publications were contacted for any unpublished research. Selection of studies was made on the basis of the following criteria: Cohort and case-control studies, pregnant women with a singleton pregnancy, exposure: HbAS or thalassaemia minor and the following outcomes: urinary tract infection (UTI), anaemia, (pre-)eclampsia, gestational diabetes, premature labour, low birth weight, intrauterine growth retardation, miscarriage, neonatal death, low Apgar score, neural tube defects. Quality assessment and data extraction were carried out by two researchers. A total of 780 subjects were identified of which nine were included in the study. A protective effect of sickle cell trait was found for premature birth, low Apgar score and perinatal mortality rate. No significant effect was found for low birth weight, growth retardation, UTI or high blood pressure. The risk of anaemia and bacteriuria was increased. In conclusion, the risks amongst pregnant HbP carriers are low. Midwives and obstetricians need to be aware of the risk of anaemia and UTI.

Iron metabolism in heterozygotes for hemoglobin E (HbE), alpha-thalassemia 1, or beta-thalassemia and in compound heterozygotes for HbE/beta-thalassemia

BACKGROUND

Despite large populations carrying traits for thalassemia in countries implementing universal iron fortification, there are few data on the absorption and utilization of iron in these persons.

OBJECTIVE

We aimed to determine whether iron absorption or utilization (or both) in women heterozygous for beta-thalassemia, alpha-thalassemia 1, or hemoglobin E (HbE) differed from that in control subjects and compound HbE/beta-thalassemia heterozygotes.

DESIGN

In Thai women (n = 103), red blood cell indexes, iron status, non-transferrin-bound iron, and growth differentiation factor 15 were measured, and body iron was calculated. Fractional iron absorption was measured from meals fortified with isotopically labeled ((57)Fe) Fe sulfate, and iron utilization was measured by the infusion of ((58)Fe) Fe citrate.

RESULTS

Iron utilization was approximately 15% lower in alpha-thalassemia 1 or beta-thalassemia heterozygotes than in controls. When corrected for differences in serum ferritin, absorption was significantly higher in the alpha- and beta-thalassemia groups, but not the HbE heterozygotes, than in controls. HbE/beta-thalassemia compound heterozygotes had lower iron utilization and higher iron absorption and body iron than did controls. Nontransferrin-bound iron and growth differentiation factor 15 were higher in the compound heterozygotes, but not in the other groups, than in the controls.

CONCLUSIONS

In alpha-thalassemia 1 and beta-thalassemia heterozygotes with ineffective erythropoesis, dietary iron absorption is not adequately down-regulated, despite a modest increase in body iron stores. In populations with a high prevalence of these traits, a program of iron fortification could include monitoring for possible iron excess and for iron deficiency.

Alpha+ -thalassaemia and pregnancy in a malaria endemic region of Papua New Guinea

The effect of maternal alpha+ -thalassaemia on pregnancy was assessed in the north coastal region of Papua New Guinea (PNG), where malaria is hyperendemic and alpha+ -thalassaemia is extremely common. In a prospective study of 987 singleton hospital deliveries, we correlated maternal alpha-globin genotype with markers of reproductive fitness (age in primigravidae, gravidity, pregnancy interval and the number of miscarriages and stillbirths), Plasmodium falciparum(P. falciparum) infection of the mother and placenta, maternal haemoglobin, preterm delivery and birthweight. The frequency of the -alpha genotype in mothers was 0.61. Markers of reproductive fitness were similar in women with and without alpha+ -thalassaemia. Median haemoglobin concentration during pregnancy and after delivery was about 1.0 g/dl lower in homozygous alpha+ -thalassaemia than in women with a normal alpha- globin genotype (P < or = 0.001). The frequency of placental P. falciparum infection and systemic malaria infection after delivery showed no consistent relationship to alpha-globin genotype. The frequency of preterm delivery and low birthweight did not vary significantly according to maternal alpha-globin genotype. Maternal alpha+ -thalassaemia does not affect reproductive fitness or susceptibility to malaria during pregnancy. Although median haemoglobin concentration was significantly lower in mothers homozygous for alpha+ -thalassaemia than those with a normal alpha-globin genotype, this did not result in an adverse outcome of pregnancy.

Iron status in anemic pregnant women

AIM

A descriptive study at a tertiary care center was carried out to assess the prevalence of iron status in anemic pregnant women and to determine the appropriate iron supplement.

METHODS

Eligible subjects were pregnant women with a hemoglobin concentration <11 g/dL. Pregnant women who received antenatal vitamin and/or iron supplements before blood testing and women with an underlying chronic disease were excluded. Hemoglobinopathy was defined by hemoglobin typing other than HbA2A, percentage of HbA2 >4%, and HbF >1.1%. We diagnosed iron deficiency and iron depletion if their serum ferritin were <12 and 20 ng/mL, respectively, whereas anemia from undetermined causes was defined by hemoglobin typing, namely: A2A, HbA2 <4% and HbF <1.1%, and serum ferritin >20 ng/mL.

RESULTS

Among the 137 anemic pregnant women recruited, 67 (49.8%) had HbA2A, 47(34.3%) HbEA, 15 (10.9%) HbEE, 3 (2.2%) HbCSA2A, 2 (1.5%) HbCSEA, 1 (0.7%) HbCSA2A Bart's, 1 (0.7%) HbEA Bart's, and 1 (0.7%) beta-thalassemia. Among the 67 women with normal hemoglobin (HbA2A), 14 (20.9%) had iron deficiency, and 12 (17.9%) iron depletion. Among the 70 women with hemoglobinopathy, 6 (8.6%) had iron deficiency, and 10 (14.3%) iron depletion.

CONCLUSIONS

Anemic pregnant women with hemoglobinopathy could also be iron deficient so will need iron supplementation, as other pregnant women do, and some iron replacement therapy.

The contribution of alpha+-thalassaemia to anaemia in a Nigerian population exposed to intense malaria transmission

The proportion to which alpha-thalassaemia contributes to anaemia in Africa is not well recognized. In an area of intense malaria transmission in South-West Nigeria, haematological parameters of alpha-thalassaemia were examined in 494 children and 119 adults. The -alpha3.7 type of alpha+-thalassaemia was observed at a gene frequency of 0.27. Nine and 36.5% of individuals were homozygous and heterozygous, respectively. P.falciparum-infection was present in 78% of children and in 39% of adults. The alpha-globin genotypes did not correlate with the prevalence of P. falciparum-infection. alpha+-thalassaemic individuals had significantly lower mean values of haemoglobin, mean corpuscular volume, and mean corpuscular haemoglobin than non-thalassaemic subjects. Anaemia was seen in 54. 7% of children with a normal alpha-globin genotype, in 69.9% of heterozygous (odds ratio: 1.99, 95% confidence interval: 1.32-3.00, P = 0.001), and in 88.4% of homozygous alpha+-thalassaemic children (odds ratio: 7.72, 95% confidence interval: 2.85-20.90, P = 0.0001). The findings show that alpha+-thalassaemia contributes essentially to mild anaemia, microcytosis, and hypochromia in Nigeria.

Frequency of coincident iron deficiency and beta-thalassaemia trait in British Asian children

A study was carried out to determine the frequency of combined iron deficiency and beta-thalassaemia trait in a cohort of British Asian children to see whether the trait protects iron status. Of 470 consecutive children with red cell microcytosis, 77 had beta-thalassaemia trait and 26 (34%) of these also had evidence of iron deficiency. It was most common and profound in children under five years of age where the prevalence was 16 in 33 (48.5%). This suggests that iron deficiency is no less common in Asian children with beta-thalassaemia trait than in those without. It should not be presumed that the trait protects iron status or that the two are in any way mutually exclusive, at least in the early years.