Diagnosis of von Willebrand disease in Western Mexico.

INTRODUCTION: Von Willebrand disease (VWD) is the most common inherited bleeding disorder with a prevalence of 0.1%, characterised by quantitative or functional deficiency of von Willebrand factor (VWF). VWD diagnosis is based on symptomology, biochemical and genetic tests, but limited laboratory resources and VWD heterogeneity still generate an important subdiagnosis gap worldwide and in our country. AIM: To identify the type and subtype of VWD in a cohort of patients with a history of excessive bleeding in Western Mexico. METHODS: This prospective cohort study from 2012 to 2019 included patients with mucocutaneous bleeding or abnormal laboratory tests. A standardised questionnaire and confirmatory tests were applied: FVIII:C, VWF activity, VWF antigen, and VWF multimeric analysis. RESULTS: Of the 297 patients recruited, 207 (69.7%) were excluded because their values exceeded 50% in VWF activity and VWF antigen. Of those 90 remaining, 54 (18.2%) had low VWF, and only 36 patients (12.1%) were diagnosed with VWD. Among them, 17 (47.2%) had quantitative deficiencies, of whom 14 were assigned as type 1 and 3 as type 3.The remaining 19 cases were diagnosed as type 2 (52.8%): type 2A and 2B were the most frequent with 6 and 7 cases respectively; 4 cases were possible type 2M and two suggestive of 2N, however, this was not confirmed. CONCLUSION: This study highlights the challenges of VWD diagnosis using a comprehensive panel of diagnostic tests which should extend to supplemental tests of VWF:CB, VWF:FVIIIB, and sequencing the VWD gene to confirm the results from the panel assays.

Genetic analysis for carrier diagnosis in hemophilia A and B in the Mexican population: 25 years of experience.

Our 25 years of experience in carrier diagnosis of hemophilia A (HA) and B (HB) in Mexican population comprises linkage analysis of intragenic F8/F9 neutral variants along with, in severe HA (SHA), detection of F8 int22h and int1h inversions. In symptomatic carriers (SCs) we explored Lyonization to explain their symtomatology. From a DNA-Bank of 3,000 samples, intragenic restriction fragment length (RFLPs) and short tandem repeats (STRs) of F8/F9 genes were assessed by PCR-PAGE and GeneScan. In SHA patients, F8 inversions were detected by inverse shifting-PCR/diagnostic and complementary tests. In SCs, we evaluated hemorrhagic symptoms, clotting FVIII/FIX and X-chromosome inactivation (XCI) patterns were assessed by HUMARA assay and the search of XIST promoter pathogenic variants. Informativeness of linkage analysis for HA carrier diagnosis with RFLP's/STR's increased to 74% and reached 80% with five RFLPs for HB. Combined Inv22/Inv1 diagnosed 113 possible carriers, three de novo Inv22-1, and confirmed 45 mothers as obligate or sporadic carriers. Among 21 SCs, four showed extreme skewed XCI pattern (~80:20) but had normal karyotype and no C43G pathogenic variant in XIST promoter. Clotting FVIII/FIX correlated with the active X in leukocytes. Our data integrate the largest comprehensive research worldwide on the molecular diagnosis of HA and HB carriers in terms of the number of studied and diagnosed cases, in addition to the genetic analysis in SCs. Intragenic RFLPs and STRs of F8/F9 genes along with F8 int22h/int1h inversions in SHA emerge as optimal variants for molecular diagnosis in Mexican population. In counseling SCs, inheritance of skewed X-inactivation should be considered.

Coronavirus Disease 2019: Hematological Anomalies and Antithrombotic Therapy.

After the first cases of COVID-19 appeared in Wuhan, China at the end of 2019, the disease quickly become a pandemic that has seriously affected the economic and health systems in more than 200 countries and territories around the world. Although most patients have mild symptoms or are even asymptomatic, there are patients who can develop serious complications such as acute respiratory distress syndrome or venous thromboembolism requiring mechanical ventilation and intensive care. Hence, it is important to identify patients with a higher risk of complications in a timely manner. Thus, the objective of this paper is to review the hematological laboratory parameters that consistently are altered in COVID-19 and to identify their relationship with the severity of the disease. According to 11 selected reports, the frequency of patients aged > 65 years is higher among subjects severely affected or deceased; likewise, males predominantly suffer from comorbidities such as hypertension, diabetes or obesity. Retrospective studies have identified alterations in various hematological and inflammatory parameters as part of the host's response to infection and a secondary increased risk of different thrombotic events. Among these altered parameters, D-dimer, C-reactive protein, and interleukin-6 have been tested as prognostic biomarkers due to their close relationship with the severity of the disease. Actually, they can reliably indicate the use of antithrombotic therapy at prophylactic or therapeutic doses (mainly D-dimer), as has already been established in those patients who, after an individualized assessment, appear to be at high risk for thrombotic events.