Factor VIII Intron 22 Inversion in Severe Hemophilia A Patients in Palestine

BACKGROUND

Hemophilia A is an X-linked recessive bleeding disorder caused by mutations in FVIII gene with an incidence of 1 in 5,000 to 10,000 live born males. The Inv22 mutation is a major cause of the disease worldwide, accounting for up to 40%-50% of severe FVIII mutations. The aim of the present study was to screen Inv22 of the FVIII gene in Palestinian patients with severe HA and reveal its role as a predisposing factor for the development of inhibitors.

MATERIALS AND METHODS

A cohort of 77 HA individuals including 5 carrier females from 52 unrelated families registered at governmental hemophilia centers in the West Bank area of Palestine was investigated. The demographic data and the clinical history were retrieved from medical files. Molecular analysis of Inv22 mutation in severe HA (30 cases) from Palestine was performed using the subcycling polymerase reaction (S-PCR). FVIII coagulant activities were carried out on an aPTT-based 1-stage clotting assay. FVIII inhibitors were quantified using the Nijmegen modification of the Bethesda assay.

RESULT

Overall, 41.7% (30/72) of the studied cases were classified as having severe HA, 22.2% (16/72) had moderate HA, and 36.1% (26/72) had mild HA. Five randomly selected carrier mothers were screened for the Inv22 mutation to confirm its transmission to their sons. The Inv22 mutation was detected in 11 severe HA patients (36.6%). Among the severe HA patients with positive Inv22, 45.5% (5/11) had developed inhibitors. The current study showed that there was no association (p=0.53) between inhibitor development and the Inv22 mutation.

CONCLUSION

Findings on Inv22 are in agreement with worldwide reports, being a major genetic mutation in severe HA. The S-PCR is a simple, rapid, and cost-effective method for the diagnosis of Inv22 in severe HA patients. Although the Inv22 mutation was associated with 36.6% of severe HA phenotype cases, it was not a major predisposing factor for inhibitor formation.

Molecular characterization of β-thalassemia intermedia in the West Bank, Palestine

BACKGROUND

We aimed to investigate the molecular basis of β-Thalassemia intermedia (TI) in the West Bank region and its management practices.

METHODS

This was a case series multi-center study and included 51 cases of TI. DNA sequencing was used to analyze β-globin gene mutations. Common α-globin gene mutations were screened by Gap-PCR (-α3.7, -α4.2, --MED, αααanti3.7) or DNA sequencing (α2-IVS II 5 nt del). XmnI -158 C > T polymorphisms of Gγ-globin gene was determined by RFLP-PCR.

RESULTS

Seven β-globin gene mutations were observed, namely IVS-I -6 C > T, IVS-I-110 G > A, IVS-II-1 G > A, IVS-I-1 G > A, Codon 37 Trp > Stop, beta - 101 and IVS-II-848 C > A. Ten genotypes were observed. Homozygosity for IVS-I-6 accounted for the majority of TI cases with a frequency of 74.5%. The second common β-globin gene genotype was homozygote IVS-I-110 G > A (5.8%) and homozygote IVS-II-1 G > A (5.8%). The remaining seven genotypes were each detected in about 2% of patients. α-Thalassemia mutations were seen in five patients (9.8%), and included (-α3.7, αααanti3.7 and α2-IVSII-5 nt del). XmnI polymorphism was observed in four patients (7.8%), three homozygotes and one heterozygote.

CONCLUSIONS

Homozygosity for the mild β-globin gene IVS-I-6 allele was the major contributing factor for the TI phenotype among the study subjects. The role of XmnI SNP and α-thalassemia mutations in ameliorating the TI phenotype was observed in few patients for each factor. The beta - 101 C > T mutation was diagnosed in one patient in homozygote state for the first time in Palestine.

Factor V Leiden G1691A and prothrombin G20210A mutations among Palestinian patients with sickle cell disease

Background

Vascular thrombosis is an important pathophysiological aspect of sickle cell disease (SCD). This study aimed to investigate the prevalence and clinical impact of factor V Leiden G1691A (FVL) and prothrombin G20210A mutations among Palestinian sickle cell disease (SCD) patients.

Methods

A total of 117 SCD patients, including 59 patients with sickle cell anemia (SS), 33 patients with sickle β-thalassemia and 25 individuals with sickle cell trait (AS) were studied. The control group consisted of 118 healthy individuals. FVL and prothrombin G20210A mutations were determined by RFLP PCR.

Results

Analysis of the clinical history of SCD patients revealed that seven patients have had vascular complications such as ischemic stroke or deep vein thrombosis. In SCD patients, the inheritance of the FVL mutation showed a significantly higher incidence of pain in joints, chest and abdomen as well as regular dependence on blood transfusion compared to SCD with the wild type. Age- and sex-adjusted logistic regression analysis revealed a significant association between FVL and sickle cell anemia with an odds ratio (OR) of 5.6 (95% confidence intervals [CI] of 1.91–39.4, P = 0.039) in SS patients. However, increased prevalence of the FVL in AS subjects and sickle β-thalassemia patients was not statistically significant compared to controls (OR 3.97, 95% CI 0.51–28.6, P = 0.17 and OR 3.59, 95% CI 0.35–41.6, P = 0.26, respectively). The distribution of prothrombin G20210A mutation among SCD patients compared to controls was not significantly different, thus our findings do not support an association of this mutation with SCD.

Conclusions

FVL was more prevalent among SS patients compared to controls and it was associated with higher incidence of disease complications among SCD patients.

Mannose binding lectin and ficolin-2 polymorphisms are associated with increased risk for bacterial infections in children with B acute lymphoblastic leukemia

BACKGROUND

We aimed to investigate whether the presence of mannose binding lectin (MBL2), ficolin 2 (FCN2) polymorphisms or the combined deficiency significantly influence the risk and subsequently the frequency of chemotherapy-induced bacterial infections in children with B acute lymphoblastic leukemia (B-ALL).

PROCEDURE

MBL2 polymorphisms for exon 1 and FCN2 polymorphisms for promoter regions -986, -602, -557, -64, -4 and exon 8 regions +6,359, +6,424 were determined in children with B-ALL. FCN2 haplotype was determined by gene sequencing. Number and duration of FN episodes as well as number of bacterial infections were recorded during induction chemotherapy.

RESULTS

Forty-four children with B-ALL (median age 4.3 years, 65.9% males) suffered from 142 FN episodes and 92 bacterial infections (40.2% Gram positive and 59.8% Gram negative). MBL2 low-risk genotype was found in 59.1%, medium-risk in 31.8% and high-risk in 9%. FCN2 low-risk haplotypes were detected in 38.2%, medium-risk in 44.1% and high-risk in 17.6%. MBL2 genotype and FCN2 haplotype were not associated with increased frequency of FN episodes. MBL2 medium/high-risk genotype and FCN2 medium/high-risk haplotype were associated with prolonged duration of FN (P = 0.007 and P = 0.001, respectively) and increased number of bacterial infections (P = 0.001 and P = 0.002, respectively). The combined MBL2/FCN2 medium/high-risk genotype was associated with an increased number of bacterial infections (P = 0.001).

CONCLUSIONS

MBL2 and FCN2 single or combined deficiencies are associated with increased duration of FN episodes as well as increased number of bacterial infections in children with B-ALL suggesting a prognostic role of these genes.

beta(S)-Globin gene cluster haplotypes in the West Bank of Palestine

Sickle cell disease is an inherited autosomal recessive disorder of the beta-globin chain. In Palestine it is accompanied by a low level of Hb F (mean 5.14%) and a severe clinical presentation. In this study, 59 Palestinian patients, homozygotes for Hb S were studied for their haplotype background. Eight polymorphic sites in the beta-globin gene cluster were examined. The Benin haplotype was predominant with a frequency of 88.1%, followed by a frequency of 5.1% for the Bantu haplotype. One chromosome was found to carry the Cameroon haplotype (0.85%). Three atypical haplotypes were also found (5.95%). Heterogeneity was observed in Hb F production, ranging between 1.5 and 17.0%, whereas the (G)gamma ratio was homogeneous among all haplotypes with a normal amount of about 41%. Our results are in agreement with previous reports of the Benin haplotype origin in the Mediterranean.