Meganathan Kannan

Inherited prothrombotic defects in Budd-Chiari syndrome and portal vein thrombosis: a study from North India.

We studied 57 patients with Budd-Chiari syndrome (BCS) and 48 with portal vein thrombosis (PVT) for underlying inherited prothrombotic defects such as protein C, protein S, and antithrombin III deficiencies. Genetic mutations for factor V Leiden, prothrombin gene 20210A, and methyltetrahydrofolate reductase (MTHFR) C677T were studied in 29 patients in each group. Inherited prothrombotic defects were detected in 16 (28%) of 57 patients with BCS and 7 (15%) of 48 patients with PVT. Factor V Leiden mutation was the most common prothrombotic defect in BCS (5/29 [17%]) followed by protein C deficiency (7/57 [12%]) and protein S deficiency (4/57 [7%]), whereas in PVT, protein C deficiency was the most common inherited prothrombotic defect (4/48 [8%]) followed by protein S deficiency (2/48 [4%]). The factor V Leiden mutation was detected in only 1 (3%) of 29 cases of PVT. The heterozygous MTHFR C677T mutation was detected in 7 (24%) of 29 patients with BCS and 6 (21%) of 29 patients with PVT. Antithrombin III deficiency, homozygous MTHFR C677T mutation, and prothrombin G20210A mutation were not detected in any patients.

Inherited Prothrombotic Defects in Budd-Chiari Syndrome and Portal Vein Thrombosis

We studied 57 patients with Budd-Chiari syndrome (BCS) and 48 with portal vein thrombosis (PVT) for underlying inherited prothrombotic defects such as protein C, protein S, and antithrombin III deficiencies. Genetic mutations for factor V Leiden, prothrombin gene 20210A, and methyltetrahydrofolate reductase (MTHFR) C677T were studied in 29 patients in each group. Inherited prothrombotic defects were detected in 16 (28%) of 57 patients with BCS and 7 (15%) of 48 patients with PVT. Factor V Leiden mutation was the most common prothrombotic defect in BCS (5/29 [17%]) followed by protein C deficiency (7/57 [12%]) and protein S deficiency (4/57 [7%]), whereas in PVT, protein C deficiency was the most common inherited prothrombotic defect (4/48 [8%]) followed by protein S deficiency (2/48 [4%]). The factor V Leiden mutation was detected in only 1 (3%) of 29 cases of PVT. The heterozygous MTHFR C677T mutation was detected in 7 (24%) of 29 patients with BCS and 6 (21%) of 29 patients with PVT. Antithrombin III deficiency, homozygous MTHFR C677T mutation, and prothrombin G20210A mutation were not detected in any patients.

Membrane array–based differential profiling of platelets during storage for 52 miRNAs associated with apoptosis

BACKGROUND: Enucleated platelets (PLTs) utilize posttranscriptional gene (mRNA) regulation (PTGR) for their normal morphologic and physiologic functions, which are altered in their ex vivo storage, also collectively referred to as storage lesions. While cellular micro‐RNAs (miRNAs) play a significant role in posttranscriptional gene (mRNA) regulation by binding to their target mRNAs, comprehensive analysis of apoptosis‐associated miRNAs and global changes in their profiles during PLT storage have not been evaluated to date.

Differential profiling of human red blood cells during storage for 52 selected microRNAs.

BACKGROUND: MicroRNAs (miRNAs), the negative regulators of cellular mRNAs, are present in mature red blood cells (RBCs) in abundance relative to other blood cells. So far, there are no studies aimed at identifying large‐scale miRNA profiles during storage of RBCs.

Molecular defects in ITGA2B and ITGB3 genes in patients with Glanzmann thrombasthenia

Summary.  Background: Glanzmann thrombasthenia (GT) is an autosomal recessive inherited platelet function defect that is characterized by reduction in, or absence of, platelet aggregation in response to multiple physiologic agonists. The defect is caused by mutations in the genes encoding ITGA2B or ITGB3. This results in qualitative or quantitative abnormalities of the platelet receptor, αIIb‐β3. Objectives: The aim of this study was to identify the mutations in GT patients and to correlate these with patient phenotype. Subjects and methods: A total of 45 unrelated patients with GT were enrolled in the present study to identify the causative molecular defects, and also to correlate their phenotype with their genotype. Platelet aggregation, flow cytometry, Western blotting, and mutation screening by conformation sensitive gel electrophoresis (CSGE) followed by sequencing were performed in all patients. Novel mutations were analyzed for penetrance in individual families. Results: A total of 22 novel mutations were identified in 45 unrelated GT patients. Mutations were identified in 36 of the 45 (80%) patients. Missense mutations were seen in most of the GT patients (59%). The remaining mutations were heterogeneous and were distributed throughout the length of the gene. Analysis of family members showed heterozygous mutations in all families. Conclusions: The severe type I GT was the most common subtype found in this study. Missense mutations were identified as the defects responsible for most GT patients. Carrier detection and genetic counseling in these families is a potentially effective alternative for decreasing the burden of severe type of GT.

Glanzmann's Thrombasthenia: An Overview

Glanzmanns thrombasthenia (GT) is an autosomal recessive inherited bleeding disorder due to a defect in platelet function. The hallmark of this disease is severely reduced/absent platelet aggregation in response to multiple physiological agonists. Bleeding signs in GT include epistaxis, bruising, gingival hemorrhage, gastrointestinal hemorrhage, hematuria, menorrhagia, and hemarthrosis. Homozygous or compound heterozygous mutations in the genes of GPIIb and GPIIIa lead to GT. A patient with GT, with no possible causative mutations in GPIIb and GPIIIa genes, may harbor defects in a regulatory element affecting the transcription of these 2 genes. GT occurs in high frequency in certain ethnic populations with an increased incidence of consanguinity such as in Indians, Iranians, Iraqi Jews, Palestinian and Jordanian Arabs, and French Gypsies. Carrier detection in GT is important to control the disorder in family members. Carrier detection can be done both by protein analysis and direct gene analysis.

Factor V Leiden—the commonest molecular defect in arterial and venous thrombophilia in India

Several genetic factors are believed to predispose to thrombophilia [1,2]. These include Factor V Leiden defect, Prothrombin G20210A and MTHFR C677T gene polymorphism. FV Leiden is the most frequent molecular defect seen in thrombophilia in Caucasians. It has been found in 20% of consecutive patients with juvenile deep vein thrombosis (DVT), 3% arterial thrombosis and about 4.2% of healthy Caucasians [3–7]. Moderate hyperhomocysetinemia secondary to homozygous C-to-T substitution at nucleotide position 677 of the 5,10 MTHFR gene, has been found to underlie 19% of arterial, 11% of venous thrombophilia and 12% of controls [8]. Mutation at nucleotide position 20210 of the prothrombin gene is believed to influence the regulation of prothrombin gene expression and is associated with approximately threefold increase in risk for DVT in the West [9]. There it has been seen in 2% of arterial and 8% of venous thrombophilia and 2.1% of controls. Since no study exists from India on molecular defects underlying arterial thrombosis [10], and only one study is available, for venous thrombosis, the aim in this study was to determine the occurrence of these mutations in Indian subjects with arterial and venous thrombosis.

Mutation reports: Intron 1 and 22 inversions in Indian haemophilics

Intron 1 and 22 inversions were looked for in 80 severe haemophilia A patients in India using PCR and multiplex Long-Distance Subcycling-PCR, respectively. Intron 1 inversion was seen in 3 (3.75%) and intron 22 inversion was seen in 35 (43.75%) patients. Of severe haemophilics, 47.5% had either of these inversions. It is thus suggested that screening for inversions may be the first step in genetic testing of Indian haemophilics.

Protein C system defects in Indian children with thrombosis

As ethnic variations are known to exist in inherited genetic defects, the clinico-haematological profile of Indian children with thrombophilia may be different from that of Caucasians. The aim of the study was to analyse the phenotypic and genotypic causes of thrombophilia in Indian children. Forty patients with arterial (21 patients) and venous (19 patients) thrombosis were the subjects of the study. Their age ranged from 6 days to 15 years. All of the patients were initially screened by Pro C Global assay. Activated protein C resistance (APCR) was measured. In cases with low Pro C Global values, protein C (PC), protein S (PS) and factor V G1691A, prothrombin G20210A and MTHFR C677T polymorphism were tested in all 40 cases. Of the 21 patients with arterial thrombosis, 4 (19%) had PC deficiency, 7 (33.3%) had PS deficiency and 1 (4.8%) had combined deficiency of PC and PS. Of the 19 patients with venous thrombosis, 5 (26.3%) each had PC and PS deficiency and 4 (21%) had combined PC and PS deficiency. Heterozygous factor V G1691A defect was seen in one (4.8%) patient with arterial thrombosis and three (15.8%) patients with venous thrombosis. Heterozygous MTHFR C677T polymorphism was seen in five (23.8%) patients with arterial thrombosis and in four (21%) patients with venous thrombosis. Prothrombin G20210A polymorphism was absent in all patients and controls. Protein C system defect is common in Indian children with thrombosis.

Hypercoagulable state in five thalassemia intermedia patients.

Fifty-three patients of thalassemia intermedia and 40 controls were studied for clinical evidence of thrombosis and laboratory evidence of hypercoagulable state. Thrombotic episodes were detected in 5 (9.4%) patients. Two of these 5 patients with thrombosis were splenectomized. Laboratory evaluation showed presence of thrombocytosis in 8 (15%), 5 of these were splenectomized. Platelet hyperaggregation was detected in 12 (22.2%) patients. Although rate of aggregation was slow in 7 (13.2%) patients, degree of aggregation was normal in these 7 patients and platelet hypoaggregation was not detected in any patient. Level of coagulation inhibitors protein C and protein S, and antithrombin III were decreased in 31 (58.4%) patients. There was no correlation between low level of protein C and protein S with hepatic dysfunction and iron overload. Antithrombin III level was decreased only in 8 (15%) patients. There was a statistically significant association between the lower level of this inhibitor and hepatic dysfunction. In conclusion, this study provides evidence for the existence of a chronic hypercoagulable state in patients with β thalassemia intermedia, and suggests that expression of a procoagulant surface by thalassemia intermedia red blood cells may be the major underlying factor giving rise to platelet and coagulation inhibitor abnormalities in these patients. These alterations are not related to iron overload or hepatic dysfunction.