Spectrum of haemoglobinopathies diagnosed by cation exchange-HPLC & modulating effects of nutritional deficiency anaemias from north India

Unresolved laboratory issues of the heterozygous state of β-thalassemia: a literature review

Although considered a mild clinical condition, many laboratory issues of the carrier state of β-thalassemia remain unresolved. Accurate laboratory screening of β-thalassemia traits is crucial for preventing the birth of a β-thalassemia major child. Identification of carriers in the laboratory is affected by factors that influence red cell indices and HbA2 quantification. Silent mutations and co-inheriting genetic and non-genetic factors affect red cell indices which decreases the effectiveness of the conventional approach. Similarly, the type of β mutation, co-inheriting genetic and non-genetic factors, and technical aspects, including the analytical method used and variations in the HbA2 cut-off values, affect the HbA2 results, leading to further confusion. However, the combination of mean corpuscular volume, mean corpuscular hemoglobin, and hemoglobin analysis increases the diagnostic accuracy. Diagnostic problems arising from non-genetic factors can be eliminated by carefully screening the patient's clinical history. However, issues due to certain genetic factors, such as Krüppel-like factor 1 gene mutations and α triplication still remain unresolved. Each laboratory should determine the population-specific reference ranges and be wary of machine-related variations of HbA2 levels, the prevalence of silent mutations in the community.

Prevalence of beta thalassemia carriers in India: a systematic review and meta-analysis

A large number of studies have reported that the prevalence of beta thalassemia carriers in India varies by ethnic groups. The objective of this study was to conduct a systematic review of the published studies and conduct a meta-analysis to determine the prevalence of beta thalassaemia carriers in India. A PubMed database search using keywords "beta thalassaemia AND India" identified 1088 articles of which 69 articles were included in the review. Studies using diagnostic tests and methods recommended by the International Council for Standardization in Haematology were used for calculation of pooled prevalence. Pooled prevalence was calculated using a random effects model using Review Manager version 5.3. Studies had screened five categories of populations, that is, the general population; tribal groups, communities not belonging to tribal groups, persons with anemia, and persons referred with a suspicion of hemoglobinopathy. This heterogeneity contributed to a high pooled prevalence of beta thalassemia carriers of 8.23% (95% CI 7.36-9.10). Sub-group analysis however yielded 3.74% (95% CI 2.52-4.97) pooled prevalence of beta thalassemia carriers in the general population. It was 4.6% (95% CI 3.2-6.2) among tribal groups. Quality of prevalence studies was limited by methodological issues including non-random sampling methods, heterogeneity of population types screened, and lack of use of recommended diagnostic cut-offs. Prevalence of beta thalassemia carriers was similar in tribal populations and the general population, indicating the need to further investigate the prevalence of beta thalassemia carriers in tribal groups.

Spectrum of hemoglobin disorders in southern Odisha, India: a hospital based study

Background:

Hemoglobin disorders are the leading health concern in the world including India. There is a paucity of literature on the spectrum of hemoglobin disorders in southern districts of Odisha state. This study was undertaken to elucidate the occurrence of different hemoglobin disorders in a tertiary health care facility of Odisha state, India.

Methods:

The study cases were suspected patients of all age groups advised for screening of different hemoglobin disorders. Hemoglobin disorders were screened by sickling slide test and high-performance liquid chromatography (HPLC) using the Variant-II hemoglobin testing system as per the manufacturer's guidelines.

Results:

Over 2 years, 2332 blood samples (including 1102 pediatric and 1230 adult cases) were investigated, out of which, 1380 (59.2%) of cases had abnormal hemoglobin disorders. The most common was sickle cell disorders (48.67%, 1135/2332) followed by β-thalassemia (11.32%, 264/2332). Some rare variants were detected as hemoglobin D^-Punjab, hemoglobin E, hemoglobin Lepore, hereditary persistence of fetal hemoglobin, hemoglobin with high P2 window, hemoglobin with high P3 window etc, Among the cases with abnormal hemoglobin disorders, 744 (53.9%), 545 (39.5%) and, 91 (6.6%) cases were found to have the heterozygous, homozygous and, double heterozygous state. Of the 188 ante-natal cases screened, 31.4% of cases had abnormal hemoglobin variants with sickle cell disorders being the most prevalent one.

Conclusion:

Along with the high occurrence of sickle cell disorders in the study area, some other rare hemoglobin disorders are also prevalent which calls for a large community-based cohort study.

Spectrum and hematological profile of hereditary anemia in North Indians: SGPGI experience

Thalassemia and other hemoglobinopathies together with red cell enzymopathies are a common cause of anemia, which can be prevented by population screening and genetic counseling. This study was designed to screen the anemic patients for thalassemia, structural hemoglobin variants and red cell enzymopathies. A total of 17047 cases were evaluated from 2009 to 2018 for thalassemia, hemoglobin variants, glucose 6 phosphate dehydrogenase deficiency, pyruvate kinase deficiency and hereditary spherocytosis. Patients' records were entered in a Microsoft excel sheet and a spectrum of disorders was evaluated. Year wise spectrum was also analyzed to see the difference in incidence at different time periods. Incidence of beta thalassemia trait and thalassemia major was found in 11.0% and 3.4% respectively, whereas other hemoglobinopathies were observed in 3.2% of the cases. G6PD deficient cases were 0.2 % and 0.4% had hereditary spherocytosis. No significant difference was observed in incidence of thalassemia and other hemoglobinopathies at different time points. This study provided a health burden and detailed spectrum and prevalence of hemoglobinopathies in North Indians high risk population which contribute toward the development of prevention strategies for better management of hemoglobinopathies. In view of high incidence of thalassemia a routine hematological screening at a primary health center may be introduced as a prospective premarital screening under a thalassemia control program. Moreover rapid and easy quantification of hemoglobin variants (Hb variants) make Cation exchange - High Performance Liquid Chromatography (CE-HPLC) a suitable diagnostic test for the routine investigation of genetic causes of anemia.

Clinico-Hematological Profile of Hb Q India: An Uncommon Hemoglobin Variant

Inherited hemoglobin disorders include thalassemias and structural variants like HbS, HbE, and HbD, Hb Lepore, HbD-Iran, Hb-H disease and HbQ India. HbQ India is an uncommon alpha-chain structural hemoglobin variant seen in North and West India. Patients are mostly asymptomatic and often present in the heterozygous state or co-inherited with beta-thalassaemia. This study was done in a tertiary care teaching hospital in North India over a period of 7 years among patients referred from antenatal and other clinics for screening of hemoglobin disorders. Complete blood count, peripheral blood smear examination and cation exchange high performance liquid chromatography (HPLC) was done to quantify various hemoglobins. HbQ India was diagnosed if the unknown variant hemoglobin was detected within the characteristic retention window. Of a total of 7530 patients screened, 31 (0.4%) were detected to have HbQ India. Of these, 25 (0.3%) patients had HbQ India trait and 6 (0.1%) patients had compound heterozygosity for HbQ India and Beta Thalassemia trait (HbQ India-BTT). All patients were clinically asymptomatic and were detected as part of the screening for hemoglobin disorders. Only two patients with HbQ India-BTT had hemoglobin less than 10 g/dL. In 25 patients with HbQ India trait, HbQ ranged from 13.6 to 24.4% and in 6 patients with HbQ India-BTT, HbQ India ranged from 7.4 to 9.0%. HbQ India is an uncommon structural hemoglobin variant. Although asymptomatic, it may cause diagnostic difficulty in the compound heterozygous state with beta thalassemia. HPLC provides a rapid, accurate and reproducible method for screening of this condition to identify and counsel individuals.

Comparison of the characteristics of two hemoglobin variants, Hb D-Iran and Hb E, eluting in the Hb A2 window

Background

Cation exchange-high performance liquid chromatography (CE-HPLC) is most commonly used to evaluate hemoglobin (Hb) variants, which elute in the Hb A2 window. This study aimed to assess prevalence of an uncommon Hb variant, Hb D-Iran, and compare its red cell parameters and peak characteristics with those of Hb E that commonly elutes in the Hb A2 window.

Methods

Generally, we assess abnormal Hb using CE-HPLC as the primary technique along with alkaline and acid electrophoresis. All cases with Hb A2 window >9%, as assessed by CE-HPLCs during 2009–2013, were selected.

Results

Twenty-nine cases with Hb D-Iran variant were identified—25 heterozygous, 2 homozygous, 1 compound heterozygous Hb D-Iran/β-thalassemia, and 1 Hb D-Iran/Hb D-Punjab. Overall prevalence of Hb D-Iran was 0.23%. Compared to patients with Hb E, those with Hb D-Iran had significantly higher Hb (12.1 vs. 11.3 g/dL, P=0.03), MCV (82.4 vs. 76.4 fL, P=0.0044), MCH (27.9 vs. 25.45 pg, P =0.0006), and MCHC (33.9 vs. 33.3 g/dL, P=0.0005). Amount of abnormal Hb (40.7 vs. 26.4%, P=0.0001) was significantly higher while retention time (3.56 vs. 3.70 min, P=0.0001) was significantly lower in Hb D-Iran than in Hb E.

Conclusion

Hb D-Iran peak can be easily missed if area and retention time of the Hb A2 window are not carefully analyzed. To distinguish between variants, careful analysis of peak area and retention time is sufficient in most cases and may be further confirmed by the second technique—alkaline electrophoresis.

C-Window Peaks on CE-HPLC are Extremely Rare in Northern India, and Only Infrequently Represent HbC

Hemoglobin C (HbC, HBB:c.19G > A) is a structural variant that has been reported rarely from India. This was a retrospective review of all high performance liquid chromatography (HPLCs) submitted over a 14 year period to a tertiary care center in North India with an aim of finding hemoglobins that elute in the C-window. Of the 32,364 HPLCs screened, 6 cases showed peaks in the C-window. Of these 6 cases, only two cases contained hemoglobin C. These was one case each of HbC/β thalassemia and compound heterozygosity for HbC and HbD. There were 4 cases which showed very similar red cell indices and chromatograms with multiple peaks eluting in D-window, C-window and an additional peak with a retention time of 4.74 min. These four cases were compound heterozygous for an α chain variant HbQ-India and a β-chain variant HbD.

A Novel Double Heterozygous Hb D-Punjab/Hb J-Meerut Hemoglobinopathy

A comprehensive laboratory diagnosis of hemoglobinopathies forms an integral part in workup of disorders of globin chain synthesis. Clinical findings, complete blood counts, peripheral smear examination along with hemoglobin (Hb) electrophoresis and/or cation exchange high performance liquid chromatography findings and parental study helps to clinch a final diagnosis. Compound heterozygous hemoglobinopathy presents with variable clinical findings and some of them are picked up on screening tests done as part of routine antenatal workup. Here we report a rare double heterozygous hemoglobinopathy of Hb D-Punjab and Hb J-Meerut in a 35 year antenatal female.

Prevalence of thalassemia and hemoglobinopathy in eastern India: A 10-year high-performance liquid chromatography study of 119,336 cases

Background:

Hereditary hemoglobin (Hb) disorders are the most commonly encountered single gene disorders in India. Proper timely identification of these disorders is of paramount importance to prevent thalassemia major and clinically severe hemoglobinopathy as well as for epidemiologic purposes.

Aims:

Our aim was to determine the prevalence of thalassemia and hemoglobinopathy in patients of a tertiary care hospital of West Bengal, India.

Materials and Methods:

This prospective study was conducted on 119,336 cases over a period of 10 years. After taking clinical history and familial history, complete hemogram report was obtained by an automated cell counter. High-performance liquid chromatography (HPLC) was performed on the samples with Bio-Rad Variant using beta thalassemia short program. Confirmatory tests were performed whenever required.

Results:

A normal Hb pattern was observed in 104,804 (87.83%) cases and abnormalities were detected in 14,532 (12.17%) patients. β (beta) thalassemia trait was the commonest abnormality found in 5,488 (4.60%) patients. HbE trait was found in 3,604 (3.02%) patients, β thalassemia major/intermedia in 1,981 (1.66%) cases, and Eβ thalassemia in 1,384 (1.16 %) cases. Other variants detected included HbE disease, sickle-cell disease, sickle β thalassemia, HbD-Punjab trait, HbQ-India trait, α-thal trait, double heterozygous state of HbS and HbE, double heterozygous state of HbS and HbD, HbJ-Meerut, hereditary persistence of fetal hemoglobin (HPFH), HbH, delta β-thal trait, and Hb Lepore.

Conclusion:

In view of the high prevalence of hemoglobinopathy in this region, a routine premarital screening program is needed for the identification and prevention of high-risk marriages and thus, prevention of the psychosocial trauma of bearing a transfusion-dependent child for life.

Detection of Abnormal Hemoglobin Variants by HPLC Method: Common Problems with Suggested Solutions

Thalassemia and thalassemic hemoglobinopathies pose serious health problem leading to severe morbidity and mortality in Indian population. Plethora of hemoglobin variants is prevalent in multiethnic Indian population. The aim of the present study was to analyze laboratory aspects, namely, hematological profile and HPLC findings of the hemoglobin variants detected, and to discuss problems that we faced in diagnosis in a routine clinical laboratory. We screened a total of 4800 cases in a hospital based population of North India in a 2-years period of by automated HPLC method using the Variant Hemoglobin Testing System (Variant II Beta Thalassemia Short Program, Bio-Rad Laboratories) under the experimental conditions specified by the manufacturer. Whole blood in EDTA was used and red cell indices were determined using automated hematology analyzer. We detected 290 cases with abnormal variants in which beta thalassemia was the most common followed by hemoglobin E. Here, we discuss the laboratory aspects of various hemoglobin disorders and diagnostic difficulties in cases like borderline HbA2 values, presence of silent mutation, alpha thalassemia gene, and few rare variants which at times require correlation with genetic study. Special attention was given to HbA2 level even in presence of a structural variant to rule out coinheritance of beta thalassemia gene.

Spectrum of Hemoglobinopathies in West Bengal, India: A CE-HPLC Study on 10407 Subjects

Hemoglobinopathies are common genetic disorders of haemoglobin. Identification of these disorders is immensely important epidemiologically and they can be prevented by population screening. The present study was carried out to evaluate the spectrum of hemoglobinopathies in the state of West Bengal by the cation-exchange high-performance liquid chromatography (CE-HPLC). A retrospective, single-center, cross-sectional study was conducted on consecutive 10,407 participants. Out of 10,407 subjects, 8,898 (85.5 %) were diagnosed as normal, 579 (5.6 %) were as β-thalassemia trait (BTT) and 522 (5.0 %) were detected as HbE carrier on HPLC study. Apart from BTT and HbE carrier ten additional variants were encountered. The present study showed that CE-HPLC is a convenient, high-throughput, labour-saving and objective screening tool for early detection and management of hemoglobinopathies.

A Comparison of Hemoglobin A2 Levels in Untreated and Treated Groups of HIV Patients on ART Including Zidovudine

Objective. To assess the level of haemoglobin A₂ in HIV patients on antiretroviral therapy (ART) including zidovudine with untreated HIV patients. Material and Methods. The study was a case control study. A total of 185 patients were included in the study; the case group included 125 HIV patients who were on antiretroviral therapy (ART) including zidovudine and 60 were in the control group who were not receiving ART. The high-performance liquid chromatography (HPLC) was done and hemoglobin A₂ level was observed; value more than 3.5% was considered significant. The Hb A₂ percentages of HIV patients were compared with those of control using an unpaired t-test. Results. The mean of Hb A₂ in case group was 3.462% (SD 0.675) and in control group it was 2.815% (SD0.246). The higher Hb A₂ value was seen in significant number of treated patients than control group (P < 0.0001). Conclusion. The clinicians, pathologists, haematologists, and genetic counsellors should be aware of effects of nutritional anaemia and ART on Hb A₂ to reduce the chances of misdiagnosis of β-thalassaemia especially in developing countries and for centres for antenatal screening.

Hemoglobin disorders in South India

Cation exchange-high performance liquid chromatography (CE-HPLC) is increasingly being used as a first line of investigation for hemoglobinopathies and thalassemias. Together with a complete blood count, the CE-HPLC is effective in categorizing hemoglobinopathies as traits, homozygous disorders and compound heterozygous disorders. We carried out a one year study in Apollo Hospitals, Chennai (Tamil Nadu, South India) during which 543 abnormal chromatogram patterns were seen. The commonest disorder we encountered was β-thalassemia trait (37.9%), followed by HbE trait (23.2%), homozygous HbE disease (18.9%), HbS trait (5.3%), HbE β-thalassemia (4.6%), HbS β-thalassemia (2.5%), β-thalassemia major (2.3%), HbH (1.6%), homozygous HbS (1.4%), HbD trait (0.7%). The average value of HbA2 in β-thalassemia minor was 5.4%. β-thalassemia major had an average HbF of 88% and in HbH the mean A2 was 1.4%. Among the HbE disorders the HbA2 + HbE was 30.1% in the heterozygous state, 90.8% in the homozygous state and 54.8% in HbE β-thalassemia. In the sickle cell disorders, HbS varied from 30.9% in the trait to 79.9% in the homozygous state to 65.6% in HbS β-thalassemia.