Heterozygous Beta-thalassemia Research Articles

Beta-thalassemia intermedia due to a complex alpha-globin rearrangement and a heterozygous beta thalassemia mutation.

The alpha-thalassaemia alleles are very frequent in the world's population. The main molecular mechanism is a large deletion with the loss of one or two alpha genes. Another type of rarer abnormality exists: the gain of alpha genes. The consequence of a gain is an overproduction of alpha-globin chains, which aggravates a beta-thalassaemia trait into an intermedia phenotype (non-transfusion-dependent thalassaemia, NTDT). Here, we report the case of a young girl referred for a beta-NTDT with a combination never described in the literature: a heterozygous beta-thalassaemia mutation associated with a copy number gain of the alpha-globin locus and -alpha 3.7 deletion on the same allele.

Moyamoya Syndrome in a Child with Beta-Thalassemia Trait: A Case Report with Review of Literature

Background: The association of moyamoya angiopathy with hematological conditions such as sickle cell anemia and beta-thalassemia major or intermedia is well-known, but moyamoya syndrome (MMS) associated with thalassemia trait is hardly reported. We report such a rare association. Clinical Description: A 7-year-old boy presented with right-sided monoparesis with right-sided focal seizures, along with right-sided upper motor neuron type facial nerve palsy. He had a history of recurrent transient episodes of limb weakness, which were unevaluated. Examination revealed pallor and mild splenomegaly. Management and Outcome: Routine investigations revealed microcytic hypochromic anemia with normal serum iron levels. High-performance liquid chromatography was suggestive of beta-thalassemia trait. Contrast-enhanced computerized tomography of the head showed infarction in the territory of the left anterior cerebral artery (ACA) and middle cerebral artery (MCA). Magnetic resonance angiography revealed significantly attenuated bilateral internal carotid arteries in the supraclinoid region with attenuated bilateral ACA and bilateral MCA along with collateral formation suggestive of moyamoya angiopathy. The final diagnosis of MMS secondary to beta-thalassemia trait was made. The child improved with aspirin and supportive management. Conclusion: MMS can be rarely associated with the beta-thalassemia trait. Such an underlying, unsuspected heterozygous beta-thalassemia (trait) may be diagnosed only after the identification of moyamoya disease following a stroke.

Haemoglobin lepore and beta thalassaemia traits – Prenatal testing by both sequence analysis and MLPA for HBB gene: A case report

Hb Lepore is a fusion globin protein made of fused chains of delta and beta globin. It is a deletion haemoglobinopathy. In homozygote form, it is similar to transfusion dependent beta thalassaemia major, and in the heterozygous form, it causes mild microcytic hypochromic anaemia. In this case report, the couple has heterozygous Hb Lepore and heterozygous beta thalassaemia, with a pregnancy of 15weeks gestation. Prenatal testing by amniocentesis and HBB gene analysis for the fetus was done by sequencing and MLPA to detect the different types of mutations present in the parents. This case report reveals the importance of MLPA to be done along with sanger sequencing, to detect all types of mutations in the HBB gene.

E54 The Ehlers-Danlos syndrome, a disease of late diagnosis: report two cases

Abstract Introduction Ehlers-Danlos syndromes (EDS) are a heterogeneous group of rare inherited collagen disorders. Clinical signs are dominated by generalized joint hyper laxity, skin hyper elasticity and tissue fragility. The diagnosis is clinical in the absence of genetic testing. There is no curative treatment but it is possible today to improve the quality of life of these patients. We report two cases of EDS from a non-consanguineous marriage, without similar cases in their families. Observations CASE 1: Mrs N.B, 31 years old, 2nd of 4 siblings, with a history of heterozygous beta thalassemia, she presented with mechanical gonalgias secondary to patellar dislocations associated with ankle sprains since the age of 5 years. On clinical examination: generalized hyper mobility (Beighton score 9/9), hyper elasticity of the skin, skin fragility, atrophic scarring, papery skin of the knees, hyper transparency of the skin, epistaxis at the slightest scratching, the rest of the somatic examination was unremarkable. The standard biological workup, X-ray and ultrasound of the knees and ankles were without abnormalities. Classic EDS (I and II) was retained according to the 2017 international classification. The patient responded to tier I analgesics. Case 2 Mrs B.L, 24 years old, the third of five siblings, with a history of bronchial asthma, presented with bilateral and symmetrical polyarthralgia affecting the large and small joints with mixed type spinal pain associated with spontaneous myalgia in a context of profound asthenia evolving for 14 years. On osteoarticular examination, generalized joint hypermobility was noted (Beighton score 9/9); on the cutaneous level, transparency and hyperextensibility of the skin with multiple ecchymoses due to tissue fragility associated with delayed healing with cutaneous hyperesthesia, all associated with exertional dyspnea, chronic abdominal pain and gastroesophageal reflux since the onset of his illness. Biologically, no inflammatory syndrome. The autoimmune workup (RF, ACPA, FAN) was negative and other investigations were without abnormalities. X-rays of the chest, hands, wrists and knees were unremarkable. The patient was classified as having hypermobile EDS (type III) according to the international classification of the disease. The patient responded only partially to analgesics (levels I, II and III) and to tricyclic antidepressants. Conclusion The diagnosis of EDS must be made early in order to ensure optimal symptomatic management. The management must be multidisciplinary, including an evaluation, a psychological follow-up, a treatment of the pain and physiotherapy.

Whole exome sequencing and rare variant association study to identify genetic modifiers, KLF1 mutations, and a novel double mutation in Thai patients with hemoglobin E/beta-thalassemia

ABSTRACTObjectivesClinical manifestations of patients with Hemoglobin E/beta-thalassemia vary from mild to severe phenotypes despite exhibiting the same genotype. Studies have partially identified genetic modifiers. We aimed to study the association between rare variants in protein-coding regions and clinical severity in Thai patients.MethodsFrom April to November 2018, a case–control study was conducted based on clinical information and DNA samples collected from Thai patients with hemoglobin E/beta-thalassemia over the age of four years. Cases were patients with severe symptoms, while patients with mild symptoms acted as controls. Whole exome sequencing and rare variant association study were used to analyze the data.ResultsAll 338 unrelated patients were classified into 165 severe and 173 mild cases. Genotypes comprised 81.4% of hemoglobin E/beta-thalassemia, 2.7% of homozygous or compound heterozygous beta-thalassemia, and 0.3% of (δβ)0 thalassemia Hb E while 15.7% of samples were not classified as beta-thalassemia. A novel cis heterozygotes of IVS I-7 (A > T) and codon 26 (G > A) was identified. Six genes (COL4A3, DLK1, FAM186A, PZP, THPO, and TRIM51) showed the strongest associations with severity (observed p-values of <0.05; significance lost after correction for multiplicity). Among known modifiers, KLF1 variants were found in four mild patients and one severe patient.ConclusionNo rare variants were identified as contributors to the clinical heterogeneity of hemoglobin E/beta-thalassemia. KLF1 mutations are potential genetic modifiers. Studies to identify genetic factors are still important and helpful for predicting severity and developing targeted therapy.

Compound heterozygous beta thalassaemia and hereditary persistence of foetal haemoglobin presenting as thalassemia intermedia

Compound heterozygous beta thalassaemia and hereditary persistence of foetal haemoglobin presenting as thalassemia intermedia

Current Status of Thalassemia Minor Studies

Thalassemia minor carriage is one of the most common causes of anemia in Mediterranean countries. This study aimed to investigate the publications in scientific journals on thalassemia minor, which is an important health problem, especially in Mediterranean countries. The goal of this study was to retrieve data from journals that were indexed in the Web of Science (WoS; Thomson Reuters, New York, NY, USA) database. The WOS Core Collection was used to retrieve comprehensive bibliometric data. Keywords related to "beta-thalassemia carrier," or "beta-thalassemia trait," thalassemia minor" or "heterozygous beta-thalassemia" were used in a search query in the WOS search engine. The time frame was specified since 10 March 2022. The analysis included information on the increase of publications, the most active countries and institutions, the most cited journals, and the mapping of publications and keywords. A total of 8618 publications were retrieved. The first article was published in 1970, and the period between 1970 and 2021 was searched. The maximum number of publications was published in the year 2021. The number of publications had increased since 2009. Most of the publications were articles (61.696 %). The publications were from more than 100 disciplines and most of them were from Hematology (49.176%). The publications were from 274 different countries. Most of the publications were from the USA, Italy, and Greece. The USA is at the top of the list in the number of publications. But with active funding and support from the governments especially the Mediterranean countries, which have a higher prevalence of thalassemia minor, the productivity of scientific research should be increased.

THE ROLE OF COMPLETE BLOOD COUNT IN PATIENTS WITH HETEROZYGOUS BETA THALASSEMIA

OBJECTIVE: The goal of this study was to compare the Mean Platelet Volume (MPV), Platelet Lymphocyte ratio, and Neutrophil Lymphocyte ratio by evaluating the parameters of Complete Blood Count in healthy children and patients with heterozygous Beta-thalassemia (HBT).MATERIAL AND METHODS: Between July 2016 and September 2019, 60 patients admitted to the pediatric hematology-oncology outpatient clinic diagnosed with HBT and 60 healthy control subjects of similar age and sex were analyzed retrospectively. Children over one year old, whose hemoglobin A2 levels were above 3.5% were included in the study population.RESULTS: A total of 120 subjects were enrolled in this study. The HBT group included 60 subjects (32 males and 28 females) and the control group included 60 (36 males and 24 females). There were no significant differences between the two groups in terms of age and gender (p=0.29 and p=0.27). Platelet count, MPV, lymphocyte, and ferritin were significantly higher in the HBT group, whereas hemoglobin was significantly lower in the HBT group as compared with the control group.CONCLUSIONS: Increased MPV and platelets in healthy HBT patients may cause hypercoagulability and may play a role with other risk factors in the predisposition of thrombosis in adult cases. There are very few studies on the incidence of thromboembolic events in cases with HBT. It is necessary to monitor adult HBT cases especially in terms of thromboembolic events, and to study with more cases.

Proteome of Stored RBC Membrane and Vesicles from Heterozygous Beta Thalassemia Donors.

Genetic characteristics of blood donors may impact the storability of blood products. Despite higher basal stress, red blood cells (RBCs) from eligible donors that are heterozygous for beta-thalassemia traits (βThal+) possess a differential nitrogen-related metabolism, and cope better with storage stress compared to the control. Nevertheless, not much is known about how storage impacts the proteome of membrane and extracellular vesicles (EVs) in βThal+. For this purpose, RBC units from twelve βThal+ donors were studied through proteomics, immunoblotting, electron microscopy, and functional ELISA assays, versus units from sex- and aged-matched controls. βThal+ RBCs exhibited less irreversible shape modifications. Their membrane proteome was characterized by different levels of structural, lipid raft, transport, chaperoning, redox, and enzyme components. The most prominent findings include the upregulation of myosin proteoforms, arginase-1, heat shock proteins, and protein kinases, but the downregulation of nitrogen-related transporters. The unique membrane proteome was also mirrored, in part, to that of βThal+ EVs. Network analysis revealed interesting connections of membrane vesiculation with storage and stress hemolysis, along with proteome control modulators of the RBC membrane. Our findings, which are in line with the mild but consistent oxidative stress these cells experience in vivo, provide insight into the physiology and aging of stored βThal+ RBCs.

A case report of coinfection of cytomegalovirus colitis and tuberculosis of the intestine in an older patient with heterozygous beta-thalassemia-induced immunodeficiency

While thalassemia major is a known immunodeficient state, reports of thalassemia minor presenting with immunodeficiency are rare. We present a 66-year-old male with acute abdomen, hemorrhagic colitis, and septic shock. He was diagnosed with coinfection of intestinal tuberculosis and cytomegalovirus colitis secondary to an immunodeficient state due to heterozygous beta-thalassemia.

Hemoglobin North Shore: A Variant Hemoglobin Associated With the Phenotype of β-Thalassemia

Hemoglobin (Hb) North Shore (beta 134 val leads to glu) is a mutant hemoglobin that is associated with the phenotype of mild heterozygous beta-thalassemia. Heterozygotes are characterized low normal hemoglobin levels or mild anemia, microcytosis, increased HbA2, and 34%-38% Hb North Shore. The mechanism of the anemia and microcytosis associated with Hb North Shore was explored by studies of hemolysate thermal instability, peripheral blood globin biosynthesis, and whole blood oxygen affinity. Hb North Shore was mildly heat unstable in comparison to normal adult hemolysate. Pulse labeling of reticulocytes with 3H-leucine showed an alpha/beta ratio of 1.35 (normal 1.0). The beta North Shore/alpha ratio was 0.22-0.27, which was less than expected on the basis of gene dosage and less than that seen for most beta-chain variants. The beta A/alpha ratio was 0.50, as would be expected. The beta North Shore/alpha ratio was 0.26 after a 15-min pulse and did not decrease during 120 min of chase. These findings suggest that suboptimal synthesis rather than posttranslational degradation is responsible for the thalassemic phenotype associated with this variant hemoglobin. These observations parallel the findings in heterozygous HbE. It is not presently known whether the thalassemia phenotype is conferred by the structural mutation itself or by another mutation cis to the beta North Shore gene.

SARS-CoV-2 and Dengue Virus Coinfection in An Adult with Heterozygous Beta Thalassemia: A Case Report from Bangladesh with Literature Review

Introduction: Coinfections are common in pandemics, but not in recorded patients with structural hemoglobin abnormalities. The COVID-19 pandemic struck Bangladesh at the beginning of March 2020, which is also an apt period for endemic Dengue fever in this monsoon region. Case Report: We report a 30-year-old man with hemoglobinopathies coinfected with SARS-CoV-2 and Dengue virus. Dengue virus was detected by ELISA. COVID-19 was confirmed by RT-PCR and Hemoglobin Electrophoresis revealed heterozygous beta-thalassemia. The patient was treated successfully at Dhaka Hospital in ICDDR,B during COVID-19 emergency response with symptomatic supportive treatment for COVID-19 and appropriate fluid therapy for dengue fever in response to daily hematocrit level. After 21 day, the patient’s RT-PCR for COVID-19 became negative. For thalassemia, the patient was advised to have genetic counseling and family screening on discharge.Conclusion: The possibility of coinfection should be considered during the Dengue fever epidemic along with the confirmatory tests for COVID-19, when any alarming signs supporting possibility of dengue fever are found in an individual. Fluid therapy for dengue fever must be maintained with utmost care to avoid adverse effect from COVID-19-Dengue coinfection and careful monitoring of oxygen saturation during the sick period of this type of case should be performed with importance.

Detection of beta-thalassemia carriers among relatives of patients with thalassemia in Menoufia Governorate

Objectives To detect thalassemia carriers among relatives of patients with thalassemia major. Background Thalassemia syndromes are a group of blood disorders inherited in autosomal recessive manner that cause hemolytic anemia because of the decreased or absent synthesis of a globin chain. Imbalances of globin chains cause hemolysis and impair erythropoiesis. Thalassemia is the most common type of genetic abnormalities in the world. It is one of the most common genetic disorders in Egypt. Thalassemia major is variably referred to as 'Cooley's anemia' and 'Mediterranean anemia.' Thalassemia minor is also called 'beta-thalassemia carrier,' 'beta-thalassemia trait,' or 'heterozygous beta-thalassemia.' Patients and methods This study includes 100 children. All of them are relatives of patients with beta-thalassemia major who attended the Pediatric Hematology Clinic, Menoufia University Hospitals, in the period from May 2015 to November 2017. The age of our group ranged from 6 months to 18 years. Complete blood count, blood film, iron profile (serum iron, serum ferritin, and total iron-binding capacity), and hemoglobin electrophoresis were done for all. Results A total of 30 (30%) children were found to be carriers of beta-thalassemia, 20 (20%) children were found to have iron-deficiency anemia, 20 (20%) children were found to be both carriers of beta-thalassemia and have iron-deficiency anemia, two (2%) children had thalassemia intermediate, two (2%) children had sickle cell trait, and 26 (26%) children were normal. Conclusion Beta-thalassemia carrier status is the most common cause of microcytic anemia among relatives of patients with beta-thalassemia major.

Noninvasive prenatal screening test for compound heterozygous beta thalassemia using an amplification refractory mutation system real-time polymerase chain reaction technique.

We propose using a modified amplification refractory mutation system real-time polymerase chain reaction (ARMS RTPCR) technique to exclude the invasive prenatal diagnosis for a non-paternally inherited beta thalassemia mutation in couples atrisk for having a baby with CHBT. The ARMS RT-PCR method was performed for 36 at-risk couples by using isolated fetal cell-free DNA from maternal plasma. The modified ARMS RT-PCR primers targeted one of the following paternally inherited beta thalassemia mutation: -28 A→G, CD17 A→T, CD 26 G→A, IVS1-1 G→T and CD 41-42 -CTTT. The method could be successfully employed for NIPST starting with the 7th week of gestation. The results showed that 19 pregnant women were negative for PIBTM (53%). After an on-track and on-time of one year, including postnatal thalassemia blood tests, none of the babies showed symptoms or signs of beta thalassemia disease. We concluded that the modified ARMS RT-PCR method was an accurate, cost-effective and feasible method for use as a NIPST for at-risk couples with the potential of having a baby with CHBT.

Evidence for Three Distinct Classes of Phenotype Severity in Beta-Thalassaemia

Background: Classification of phenotype severity in patients with beta-thalassaemia has so far relied mainly on expert opinion using parameters of genotype, clinical features at diagnosis, and transfusion requirement. The aim of this study was to use a large dataset of patients with beta-thalassaemia and evaluate a classification system based on onset variables agreed on by an international expert group, including age at diagnosis, at first transfusion, and at first iron chelation. Methods: A retrospective dataset of 7910 patients with homozygous or compound heterozygous beta-thalassaemia was used and subjected to cluster and classification analysis starting with the onset variables. Results: Cluster analysis suggested that three clusters with minimal overlapping exist. Three phenotype severity classes (mild, moderate, severe) were accordingly assigned which showed statistically significant descending variation of age at diagnosis and start of transfusion and iron chelation. The estimated classification error rate was only 3.07% with an accuracy of 96.93%. It was evident that severe patients had higher blood requirement and iron overload levels and showed a younger age for mortality especially from heart disease. Although mild and moderate patients showed the opposite in gradual severity, they still showed evidence of high morbidity rate for complications that require longer time to manifest (eg liver damage and hepatocellular carcinoma). Conclusion: Age of diagnosis and start of transfusion and iron chelation distinguish three classes of phenotype severity in beta-thalassaemia that carry unique clinical profiles. Further prospective studies are recommended to validate these findings. Funding Statement: The authors state: None Declaration of Interests: The authors state: None to disclose. Ethics Approval Statement: An International Health Repository (IHR) protocol, approved on May 25th, 2017 by the Italian Ethical Committee (EudraCT and Sponsor's Protocol Code Numbers were 2017-004457-17 and 143AOR2017) was established to allow collection of relevant data.

Genotype-phenotype correlation among beta-thalassemia and beta-thalassemia/HbE disease in Thai children: predictable clinical spectrum using genotypic analysis.

IntroductionBeta-thalassemia is a group of inherited hemolytic anemias and one of the most common genetic disorders in Thailand. The clinical spectrum of beta-thalassemia disease ranges from mild to severe clinical symptoms including mild beta-thalassemia intermedia (TI) and severe beta-thalassemia major (TM).ObjectiveThis study aimed to determine the correlation between beta-globin gene (HBB) mutations and their phenotypic manifestations by evaluating patients’ clinical characteristics, transfusion requirements, growth and hematologic parameters, and hemoglobin typing among pediatric patients treated at Phramongkutklao Hospital.Materials and methodsSeventy beta-thalassemia patients, including 63 with beta-thalassemia/hemoglobin E (HbE) and 7 with either homozygous or compound heterozygous beta-thalassemia, were enrolled in this study. Their clinical presentation, growth parameters and laboratory findings were reviewed and analyzed. The mean follow-up time was 10.52±5.62 years. Mutation analysis in each individual was performed using multiplex amplification refractory mutation system (M-ARMS), direct DNA sequencing of beta-globin gene and gap PCR for 3.4 kb deletion detection.ResultsAll 7 homozygous and compound heterozygous beta-thalassemia patients were classified in TM. Among 63 patients with beta-thalassemia/HbE, 58 were classified in TM and 4 were classified in TI. Mean age at diagnosis was 0.8±0.49 years for homozygous or compound heterozygous beta-thalassemia and 3.43±3.5 years for beta-thalassemia/HbE. The most common HBB mutation was HBB:c.126_129delCTTT [codon 41/42 (-TCTT)] found in 34 alleles (48.6%). The height for age was also lower in homozygous beta-thalassemia patients (<3rd percentile) compared to compound heterozygous beta-thalassemia patients (25–50th percentile).ConclusionThis study revealed a genotype–phenotype correlation of the most prevalent beta-thalassemia in Thai children using diagnostic capacity in genotypic analysis of HBB mutation. Our findings can provide a better prediction of clinical manifestation and severity by early identification of the type of the HBB mutations.

Report of Beta Thalassemia in Newar Ethinicity

Beta thalassemia trait is a heterogeneous autosomal recessive form of beta thalassemia. Individual with beta thalassemia are clinically asymptomatic. Here we have described a case that has been incidentally diagnosed as beta thalassemia trait. A 31 year old male form Newar Community came to hospital for routine health checkup was send for hematological investigation. On examination, his red cell morphology was found to be microcytic hypochromic and his hemoglobin concentration was mildly decrease. His other parameters was evaluated and requested for analysis of iron profile and hemoglobin electrophoresis. Iron profile test was normal. Hemoglobin electrophoresis showed prominent band in HbA2 region. Presence of HbA2 band was confirmed by hemoglobin variant HPLC analysis. A diagnosis of heterozygous beta thalassemia trait was made. Prevalence of beta thalassemia gene in Tharu population was reported but its presence in other communities is still unknown so it is recommended to study the prevalence of beta thalassemia gene in Newar community as well.

Mean Platelet Volume in Heterozygous Beta Thalassaemia

Background/Aim: It is not known why cerebrovascular and cardiovascular ischaemic events are less frequently observed in heterozygous beta thalassaemia (HBT) patients than in the general population. However, we previously reported that serum levels of some platelet function markers, i.e. soluble CD40 ligand and soluble P-selectin, are lower in patients with HBT than in controls. A high mean platelet volume (MPV) is an indicator of in vivo platelet activation and may indicate a tendency to thrombosis. We investigated whether MPV is lower in HBT patients than in controls. Methods: Forty-eight patients with HBT were compared with 51 controls matched for gender, age, and BMI for MPV in a cross-sectional study. Results: The MPV was within the normal range and higher in the HBT group (9.64 ± 1.20 vs. 9.07 ± 082 fL, p = 0.006). The 2 groups were similar in terms of atherosclerosis risk factors and medications. After linear regression analysis, the MPV was correlated with HBT, sensitive CRP, and BMI. Conclusion: The higher MPV in patients with HBT could indicate platelet activation, and this may represent a dilemma. Higher MPV in the HBT group might have resulted from higher sympathetic nervous system activity, mild ineffective erythropoiesis, and haemolysis.

Expression néonatale d’un trait bêta-thalassémique associé à une sphérocytose héréditaire chez deux jumelles monozygotes

The beta-thalassemia trait is a heterozygous beta-thalassemia characterized by a partial deficiency of the synthesis of beta-globin chains of hemoglobin. It is usually asymptomatic and the diagnosis is often made on the occasion of the completion of a systematic blood count or a family survey. Clinical expression during the neonatal period is impossible and its association with hereditary spherocytosis is common. We report two monozygotic twins who, on the 3rd day of life, presented intense jaundice, unconjugated bilirubin associated with anemia, without hepatosplenomegaly. Laboratory tests found nonimmune hemolytic anemia with microcytosis and hypochromia justifying iterative blood transfusions. The etiological investigation found heterozygous beta-thalassemia associated with hereditary spherocytosis. The family investigation and molecular analysis objectified the beta-thalassemic mutation IVS1nt110 (G→A) in the heterozygous state in the twins, the father, the mother, and in one of the two brothers. With any nonimmune hemolytic anemia in newborns, the etiological investigation should be systematic for early diagnosis and to plan appropriate treatment.

Could Heterozygous Beta Thalassemia Provide Protection Against Multiple Sclerosis?

BackgroundHeterozygous beta thalassemia (HBT) has been proposed to increase the risk of developing autoimmune disease. Our aim in this study was to examine the prevalence of HBT among multiple sclerosis (MS) patients.Material/MethodsHBT frequency was investigated in our MS group (243 patients with MS). Hemoglobin electrophoresis (HE) was carried out if MS patients had a mean corpuscular volume of (MCV) <80 fL and a mean corpuscular hemoglobin level of (MCH) <27 pg/L according to a complete blood count (CBC). If MCV was lower than 80 fL, MCH was lower than 27 pg/L, and Hemoglobin A2 equal to or higher than 3.5%, a diagnosis of HBT was established. The frequency of patients with HBT in our MS patient group was statistically compared with the prevalence of HBT in the city of Istanbul, where our MS patients lived.ResultsThe HBT prevalence was 0.823% (2 patients) in the MS patient group. The prevalence of HBT in Istanbul has been reported to be 4.5%. According to the z-test, the HBT prevalence in our MS patient group was significantly lower than that in Istanbul (Z=6.3611, two-sided p value <0.0001, 95% confidence interval of prevalence of HBT in our MS patient group: 0.000998–0.029413).ConclusionsContrary to our hypothesis at the outset of study, the reduced HBT prevalence in the MS group compared to HBT frequency in the city of Istanbul might indicate that HBT is protective against MS.