Biochemical and Molecular Analysis of the Hb Lepore Boston Washington in a Syrian Homozygous Child

Genotype and phenotype analysis of α-thalassemia fusion gene in southern China

OBJECTIVE

The α-globin fusion gene between the HBA2 and HBAP1 genes, is clinically important in thalassemia screening because this fusion gene can cause severe hemoglobin (Hb) H disease when combined with α0 -thalassemia (α0 -thal). In this study, we evaluate the red blood cell parameters of α-thalassemia fusion gene in southern China.

METHOD

Study samples suspected of α-thalassemia fusion gene were collected and confirmed by PCR-sequencing from one medical lab center in southern China. Their genotypes and phenotypes were analyzed.

RESULTS

A total of 266 cases of α-thalassemia fusion gene were confirmed in our lab from 2017 to 2023, most of them were from Hainan province (169 cases) and Huadu district of Guangzhou (21 cases), the nationality of 143 cases from Hainan was identified, with 71.3% (102/143) being from the Li minority. The Hb, MCV, MCH for αα/(αα)fusion in adult males were 143.5±11.83g/L, 81.51±4.39 fl, and 26.26±1.29 pg, respectively; and in females, they were 126.69±12.89 g/L, 80.10±4.05 fl, 25.8±2.04 pg, respectively. All 12 cases (αα) Fusion/ --SEA showed anemia with decreased Hb, MCV and MCH.

CONCLUSION

The carriers of α-globin fusion gene heterozygotes are clinically silent and exhibit an α+ phenotype. Individuals with (αα)Fusion/--SEA show apparent anemia. This α-globin fusion gene is relatively common in southern China, specifically among the Li minority of Hainan province. Therefore, it should be taken into account for genetic counseling purposes.

Abnormal hemoglobin anti-Lepore Hong Kong compound with β0-thalassemia ameliorate thalassemia severity when co-inherited with α-thalassemia

Abnormal hemoglobin anti-Lepore Hong Kong is a rare βδ fusion variants resulting from non-homologous crossover during meiosis. Anti-Lepore Hong Kong is known to consistently exhibit significantly increased level of HbA2. In this study, we used multiplex ligation-dependent probe amplification (MLPA) and single molecular real-time (SMRT) sequencing, as well as Sanger sequencing, to identify variants in five unrelated families with abnormal elevated HbA2 level. All probands in these five families were found to be heterozygous for anti-Lepore Hong Kong. Among them, two families showed co-occurrence of β0-thalassemia and α-thalassemia (-SEA/ or αCSα/). Heterozygotes for anti-Lepore Hong Kong displayed an average HbA2 level of 17.7% and behaved normal. However, when combined with β0-thalassemia and α-thalassemia, the probands exhibited higher HbA2 level (30.2-40.8%) and behaved with β-thalassemia trait. Furthermore, determination of the α/β-mRNA ratio revealed a slight downregulation of β-globin, similar to that of β-thalassemia minor. Our study is the first to identify compound heterozygotes for anti-Lepore Hong Kong, β0-thalassemia and α-thalassemia, provide valuable information for prenatal counseling.

Spectrum of Beta-Thalassemia Mutations in Potential Carriers with Microcytic Hypochromic Anemia from Mazandaran and Golestan, Northern Provinces of Iran

Introduction

β-Thalassaemia is the most common genetic disorder and is considered as a major public health concern in Iran. Different countrywide studies have shown a heterogeneous mutational basis of β-thalassaemia with different frequencies in each area. This study is aimed at investigating the common and rare mutations in Mazandaran and Golestan, northern provinces of Iran.

Methods

5425 microcytic and hypochromic individuals were investigated from Mazandaran and Golestan provinces. From these, 1323 beta carrier or affected individuals were selected where 938 persons were from Mazandaran and 385 people were from Golestan province, respectively.

Result

53 different mutations were identified, IVSII-1 (G>A) was the most common (59.14%) followed by Cd 22/23/24 (-7 bp) (5.34%), Cd 8 (-AA) (4.93%), Cd30 (G>A) (4.00%), and IVSI-5 (G>C) (3.70%) with a total of 77.11% in Mazandaran Province, respectively. In Golestan Province, IVSI-5 (G>C) was the most frequent (44.62%) followed by IVSII-1 (G>A) (27.18%), Cd 15 (TGG>TAG) (4.36%), Fr 8/9(+G) (3.85%), and Cd 8(-AA) (2.05%) with a total of 82.06%, respectively. From the 53 different mutations, 22 numbers have been observed in both provinces. Two deletions of the beta gene named Sicilian and Asian-Indian have been detected in Mazandaran with a frequency of 0.72% each.

Conclusion

The 53 different mutations identified in this study were the most ever reported mutations in the country. Due to diversity of different ethnic groups, there are many varieties of mutation in beta globin gene in Iran. It could be assumed that both founder effect and natural selection caused by migration from neighboring areas have complemented each other to produce the high frequency of unique alleles within each region.

A Novel Frameshift Mutation, Deletion of HBB:c.199_202delAAAG [Codon 66/67 (-AAAG)] in β-Thalassemia Major Patients from the Western Region of Uttar Pradesh, India

Purpose

Beta thalassemia is one of the most common inherited disorders in India with heterogenous clinical phenotypes from silent carrier to clinically severe ones. Our study aimed to characterize the mutation spectrum in thalassemia patients who are coming to the hospital for follow-up from the western region of Uttar Pradesh India.

Patients and Methods

For the study, a case series of the retrospective bi-centre study was conducted. The patients from two thalassemia centers in the major hospitals (LLRMC Meerut, and JNMC, Aligarh administered by the Ministry of Health and Family Welfare (MoHFW)) in the Western Uttar Pradesh, India were considered for the study. A total of 77 blood samples were obtained from individuals (both related and unrelated) diagnosed with β-thalassemia after their consent. After DNA extraction, HBB gene amplification, mutation-specific polymerase chain reaction and gene sequencing were carried out to analyze the mutations.

Results

In this study, seven different types of mutations were reported for the first time in Western Uttar Pradesh, India. A novel frameshift mutation, deletion of 4 nucleotides Codon 66/67 (-AAAG) in exon 2 region, is reported for the first time. IVS 1-5 (G>C) and Codon 41/42 (-CTTT) are the most frequently reported mutations. The molecular spectrum for these two cases consists of 44 and 42 alleles out of 108 alleles, respectively.

Conclusion

A total of 108 β-thalassemia alleles were studied from 46 homozygous and 31 compound heterozygous patients. All the individuals were from 20 districts of the Western Uttar Pradesh, India.