A computational study of structural analysis of Class I human glucose-6-phosphate dehydrogenase (G6PD) variants: Elaborating the correlation to chronic non-spherocytic hemolytic anemia (CNSHA).

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzyme defect that affects more than 500 million people worldwide. Individuals affected with G6PD deficiency may occasionally suffer mild-to-severe chronic hemolytic anemia. Chronic non-spherocytic hemolytic anemia (CNSHA) is a potential result of the Class I G6PD variants. This comparative computational study attempted to correct the defect in variants structure by docking the AG1 molecule to selected Class I G6PD variants [G6PDNashville (Arg393His), G6PDAlhambra (Val394Leu), and G6PDDurham (Lys238Arg)] at the dimer interface and structural NADP+ binding site. It was followed by an analysis of the enzyme conformations before and after binding to the AG1 molecule using the molecular dynamics simulation (MDS) approach, while the severity of CNSHA was determined via root-mean-square deviation (RMSD), root-mean-square fluctuation (RMSF), hydrogen bonds, salt bridges, radius of gyration (Rg), solvent accessible surface area analysis (SASA), and principal component analysis (PCA). The results revealed that G6PDNashville (Arg393His) and G6PDDurham (Lys238Arg) had lost the direct contact with structural NADP+ and salt bridges at Glu419 - Arg427 and Glu206 - Lys407 were disrupted in all selected variants. Furthermore, the AG1 molecule re-stabilized the enzyme structure by restoring the missing interactions. Bioinformatics approaches were also used to conduct a detailed structural analysis of the G6PD enzyme at a molecular level to understand the implications of these variants toward enzyme function. Our findings suggest that despite the lack of treatment for G6PDD to date, AG1 remains a novel molecule that promotes activation in a variety of G6PD variants.

Inherited Bleeding Disorders in Pediatric Patients; experience of the national referral center in Iraq.

BACKGROUND: Inherited bleeding disorders can lead to lifelong bleeding; they are mainly caused by quantitative or qualitative defect of coagulation factors, von Willebrand factor (VWF) or platelets. No published data are available about the different types of inherited bleeding disorders in Iraq. OBJECTIVES: To describe types, severity and presentation of inherited bleeding disorders in pediatric patients in the major referral center in Iraq. PATIENTS AND METHODS: This is a cohort prospective descriptive study conducted at the National Center of Hematology, a referral center for bleeding disorders in Baghdad-Iraq, from January 2015 to December 2019. One hundred ninety-one patients, aged 1 day to 14 years, with suspected inherited bleeding disorder are included in this study. Each patient was interviewed, accompanied by a chaperone, mostly parent(s), with revision of personal and familial bleeding history, conducting a brief medical examination, and withdrawing blood for complete blood count, peripheral blood film, bleeding time, PT and APTT. Further investigations including mixing studies, lupus anticoagulant, clotting factor activity, VWF:antigen (VWF:Ag), VWF: Ristocetin cofactor (VWF:RiCof) and platelet function tests using light transmission aggregometry were performed only if indicated. RESULTS: The mean ± 1SD of age of patients is 5.3 ± 3 years, with a male:female ratio of 1.3:1. Family history of a similar bleeding disorder is recorded in 44.9% patients (P < 0.05). Consanguineous marriage was observed in 70.8% of the families (P < 0.001). The most prevalent inherited bleeding disorder is von Willebrand disease (VWD) (43.9%), of which type 3 is the most common (86.9%). Thrombasthenia is the second most prevalent (39.8%) inherited bleeding disorder; of these, the majority have Glanzmann's thrombasthenia (82.9%). Hemophilia A is found in 9.4% of patients. CONCLUSION: Type 3 VWD, Glanzmann's thrombasthenia and hemophilia A are the most common inherited bleeding disorders in the central part of Iraq, collectively they constitute >86% of patients. Consanguineous marriage should be discouraged in our society to decrease hereditary bleeding disorders. Also, there is a need to increase awareness and knowledge of bleeding disorders to improve early identification, mitigate the risk of further bleeding and prevent complications.

Presentation and diagnosis of patients with type 3 von Willebrand disease in resources-limited laboratory.

Von Willebrand disease (VWD) is a bleeding disorder that results from decreased von Willebrand factor (VWF) activity <0.30 iu/mL. Therefore, the diagnosis of type 3 VWD in patients with bleeding requires finding a VWF:Ag and/or VWF:platelet ristocetin cofactor (RiCof) <0.03 iu/mL, no further testing is usually necessary. This is a cohort study that included 64 patients with type 3 VWD who were presented and diagnosed at the National Center of Hematology (NCH) from October 2014 to October 2016. In this study the sensitivity of VWF:Ag is only 78%, the sensitivity of VWF:RiCof is 92% of diagnosed cases. From our results it can be concluded that patients with type 3 VWD are usually presented with moderate/severe mucocutaneous bleeding that is associated with prolonged bleeding time test of >10 min and a family history of similar type of bleeding. This fact was frequently utilized to provisionally diagnose several members of the same family, forming a cohort of patients that is larger than the number of objectively-diagnosed patients included in this study, when they cannot afford to be all tested with VWF:Ag/VWF:RiCof.