No abstract

We have identified 21 different alpha-galactosidase A gene (GLA) mutations in 22 unrelated Czech and Slovak families with Fabry disease. Eleven of these mutations were novel (point mutations D93N, A135V, D155H, G171R, Q280K, G360S, Q330X, splicing errors c.194ins14, c.801ins36 and deletions c.674_732del59, g.3405_6021del2617). Genotyping of family members for family-specific mutations revealed 55 heterozygotes that manifested clinical symptoms of different severity. To examine the contribution of X-inactivation skewing to disease manifestation in Fabry heterozygotes, we have adopted the Mainz severity scoring scheme and compared the score values with the X-inactivation status in 39 carriers in an age-dependent manner. The age-score trendline of Fabry females who had a predominantly inactivated X-chromosome bearing a wild-type GLA allele (10 of 38 females) was markedly steeper than in the rest of the cohort. One female carrier with an inactivated mutated allele had a low score value when compared to the other heterozygotes of the same age. These data suggest that X-inactivation is indeed a major factor determining the severity of clinical involvement in Fabry heterozygotes. There was a statistically significant difference between the severity score values of heterozygotes with random and non-random X-chromosome inactivation at the 5% level of significance. Further studies will show if the degree of the wildtype allele inactivation will be useful as a predictive marker of severity of phenotype in Fabry heterozygotes. Although the correlation between X-inactivation skewing and presentation of the disease in Fabry heterozygotes has previously been suggested in the literature, this report is among the first attempts to examine this relationship systematically.

COVID-19 is also manifested with hypercoagulability, pulmonary intravascular coagulation, microangiopathy, and venous thromboembolism (VTE) or arterial thrombosis. Predisposing risk factors to severe COVID-19 are male sex, underlying cardiovascular disease, or cardiovascular risk factors including noncontrolled diabetes mellitus or arterial hypertension, obesity, and advanced age. The VAS-European Independent Foundation in Angiology/Vascular Medicine draws attention to patients with vascular disease (VD) and presents an integral strategy for the management of patients with VD or cardiovascular risk factors (VD-CVR) and COVID-19. VAS recommends (1) a COVID-19-oriented primary health care network for patients with VD-CVR for identification of patients with VD-CVR in the community and patients' education for disease symptoms, use of eHealth technology, adherence to the antithrombotic and vascular regulating treatments, and (2) close medical follow-up for efficacious control of VD progression and prompt application of physical and social distancing measures in case of new epidemic waves. For patients with VD-CVR who receive home treatment for COVID-19, VAS recommends assessment for (1) disease worsening risk and prioritized hospitalization of those at high risk and (2) VTE risk assessment and thromboprophylaxis with rivaroxaban, betrixaban, or low-molecular-weight heparin (LMWH) for those at high risk. For hospitalized patients with VD-CVR and COVID-19, VAS recommends (1) routine thromboprophylaxis with weight-adjusted intermediate doses of LMWH (unless contraindication); (2) LMWH as the drug of choice over unfractionated heparin or direct oral anticoagulants for the treatment of VTE or hypercoagulability; (3) careful evaluation of the risk for disease worsening and prompt application of targeted antiviral or convalescence treatments; (4) monitoring of D-dimer for optimization of the antithrombotic treatment; and (5) evaluation of the risk of VTE before hospital discharge using the IMPROVE-D-dimer score and prolonged post-discharge thromboprophylaxis with rivaroxaban, betrixaban, or LMWH.

We have demonstrated a clinically relevant age- and sex-dependent progressive pulmonary involvement in AFD patients. The effects of enzyme replacement therapy on pulmonary involvement remain to be demonstrated.

Fabry disease is an X-linked recessive genetic disorder of glycosphingolipid metabolism, due to deficiency of the lysosomal enzyme alpha-galactosidase A. The disease is characterized by the progressive intracellular lysosomal accumulation of neutral glycosphingolipids throughout the body, including the cardiovascular system. It has been reported that cardiac involvement could be the sole manifestation of the disease in some patients. Myocardial abnormalities are characterized mainly by left ventricular (LV) wall thickening without significant cavity dilatation, the most frequent abnormal structural pattern being concentric LV hypertrophy (LVH). In some patients the disease mimics a typical hypertrophic obstructive cardiomyopathy. According to our experience, systolic function is largely preserved in a large majority of affected individuals. In contrast, mild to moderate impairment of diastolic filling is a relatively common finding, representing probably the most important cause of dyspnoea in patients with Fabry disease. However, in a relatively large population of affected patients, severe diastolic dysfunction, typical of restrictive cardiomyopathy, was not found. Valvular structural abnormalities are frequent due to valvular infiltration. In several patients, hypertrophy of papillary muscles and/or systolic anterior motion of the mitral leaflets associated with LV outflow obstruction may aggravate the mitral valve dysfunction. We did not confirm the previously reported high prevalence of mitral valve prolapse. Valvular regurgitation seems to be relatively frequent but mostly non-significant. Electrocardiographic changes in Fabry disease are multiple and include atrioventricular (AV) conduction abnormalities (abbreviation of the P-R interval or AV blocks), signs of LVH and repolarization abnormalities. Our observations suggest that conduction defects and repolarization changes are present predominantly in subjects with LV structural abnormalities. Cardiac symptoms in patients with Fabry disease include shortness of breath on effort (related to LV diastolic dysfunction), vasospastic and/or exertional angina pectoris (due to LVH, endothelial dysfunction and/or fixed coronary artery stenosis) and syncope (related to AV blocks or LV outflow obstruction). The extent of cardiac involvement, in particular LV mass assessment, could represent an ideal surrogate endpoint for evaluating the efficacy of specific therapies.