Impact of COVID-19 Infection among Indian Sickle Cell Disease Patients

Background: Sickle cell disease (SCD) is one of the most common hemoglobinopathy disorders and is widely prevalent in India, especially in the tribal population. SCD patients are prone to develop recurrent respiratory infections and related complications owing to the microvascular occlusion and impaired immunological response. Objectives: We aimed to determine the prevalence and impact of COVID‑19 in SCD patients from India. Methodology: We conducted a cross‑sectional study in Chandrapur district of Maharashtra, India, between August and October 2021. After taking informed consent, details of 300 SCD patients’ demographic data, history of COVID‑19 testing, infection, symptoms related to COVID‑19 in the past 1 year, hospitalization, complications, mortality, COVID‑19 vaccination, and side effects were recorded. Results: We found that 93 (31%) of SCD patients had influenza‑like symptoms during the COVID‑19 pandemic with symptoms of fever (81.72%), cough (35.48%), sore throat (18.27%), headache (15.05%), and breathlessness(7.52%). Atotal of 13 (4.33%) SCD among 300 SCD were tested as COVID positive. Majority of them were mild cases and the 1st dose of COVID‑19 vaccine was received by 47 (29.37%) of SCD patients and 10 (6.02%) of the patient had received second dose of vaccine. Conclusion: Low incidence of COVID‑19 and milder disease spectrum in our study cohort suggests that there is no increased risk of COVID‑19 mortality and morbidity in SCD patients compared to general population. However, the reason for low COVID vaccination in our study could be due to the fear of complications of COVID vaccine.

Diagnostic challenges posed by a rare alpha globin chain variant Hb Fontainebleau in a pregnant female and its potential effects in her children in view of multiple globin gene defects in her husband

Alpha globin chain variants per se do not cause severe morbidity and mortality but can modify – usually ameliorate – the clinical manifestations of beta globin chain variants when co-inherited with the latter. They also pose challenges in interpretation of high-performance liquid chromatography histograms and require molecular analysis for proper characterization. Hemoglobin (Hb) Fontainebleau is a rare alpha globin chain variant [alpha 21(B2) Ala?Pro], of which only three families have been reported from India in the past. Here, we describe a case of Hb fontainebleau detected in heterozygous condition in a 19-year-old primigravida. Her husband was found to have a double heterozygous state for HbQ India and beta-thalassemia trait. This opens up the possibility of multiple combinations of hemoglobinopathies in the offspring.

Invasive & non-invasive approaches for prenatal diagnosis of haemoglobinopathies: Experiences from India.

The thalassaemias and sickle cell disease are the commonest monogenic disorders in India. There are an estimated 7500 - 12,000 babies with β-thalassaemia major born every year in the country. While the overall prevalence of carriers in different States varies from 1.5 to 4 per cent, recent work has shown considerable variations in frequencies even within States. Thus, micromapping would help to determine the true burden of the disease. Although screening in antenatal clinics is being done at many centres, only 15-20 per cent of pregnant women register in antenatal clinics in public hospitals in the first trimester of pregnancy. There are only a handful of centres in major cities in this vast country where prenatal diagnosis is done. There is considerable molecular heterogeneity with 64 mutations identified, of which 6 to 7 common mutations account for 80-90 per cent of mutant alleles. First trimester foetal diagnosis is done by chorionic villus sampling (CVS) and DNA analysis using reverse dot blot hybridization, amplification refractory mutation system (ARMS) and DNA sequencing. Second trimester diagnosis is done by cordocentesis and foetal blood analysis on HPLC at a few centres. Our experience on prenatal diagnosis of haemoglobinopathies in 2221 pregnancies has shown that >90 per cent of couples were referred for prenatal diagnosis of β-thalassaemia after having one or more affected children while about 35 per cent of couples were referred for prenatal diagnosis of sickle cell disorders prospectively. There is a clear need for more data from India on non-invasive approaches for prenatal diagnosis.

HPLC studies in hemoglobinopathies.

An accurate diagnosis of beta -thalassemia carriers, homozygous patients and identification of different structural hemoglobin variants is important for epidemiological studies as well as for management and prevention of the major hemoglobin disorders. There are many electrophoretic and chromatographic approaches for estimation of HbA2 and Hb F but cation exchange HPLC (CE-HPLC)using automated dedicated machines like the Variant Hb testing system have become the method of choice for these investigations. CE-HPLC also helps in the presumptive identification of many abnormal hemoglobin variants and has been useful for both neonatal screening of sickle cell disease as well as second trimester prenatal diagnosis of thalassemia by fetal blood analysis. Other applications of HPLC in hemoglobinopathies include separation of globin chains, measuring the ratio of gamma globin chains (Ggamma/Agamma) and the recently described denaturing HPLC for detecting mutations in both alpha and beta globin genes.

Variable clinical severity of Hb E beta-thalassemia among Indians.

OBJECTIVE: The aim of this preliminary report was to look at the effect of genetic variations in the alpha, beta and gamma globin genes in 7 cases of hemoglobin E/beta-thalassemia with diverse clinical expression of the disease. METHODS: beta-thalassemia mutations were characterized by PCR and dot blot hybridization. G gamma gene polymorphism (Xmnl) was determined by PCR followed by restriction enzyme digestion and polyacrylamide gel electrophoresis. alpha genotyping was done by Southern blot hybridization. RESULTS: Six cases had a severe beta+ mutation [IVS 1 nt 5 (G-->C)] and one case had a beta zero mutation [F/S 41/42 (-CTTT)]. Hence, the beta-thalassemia mutation does not seem to contribute towards the clinical diversity. alpha-genotyping showed a single alpha-gene deletion of the rightward type in three of the five milder cases. The -158 G gamma (C-->T) substitution was present at least in heterozygous state (+/-) in all the milder cases. CONCLUSIONS: Deletional alpha thalassemia and presence of the -158 G gamma (C->T) substitution are the two factors which appear to be more important in decreasing the severity of the disease rather than the nature of the beta thalassemia mutation.