Fabry Disease: prevalence of affected males and heterozygotes with pathogenic <i>GLA</i> mutations identified by screening renal, cardiac and stroke clinics, 1995-2017.

Abstract

Fabry Disease (FD), an X linked lysosomal storage disease due to pathogenic α-galactosidase A (<i>GLA</i>) mutations, results in two major subtypes, the early-onset Type 1 'Classic' and the Type 2 'Later-Onset' phenotypes. To identify previously unrecognised patients, investigators screened cardiac, renal and stroke clinics by enzyme assays. However, some screening studies did not perform confirmatory <i>GLA</i> mutation analyses, and many included recently recognised 'benign/likely-benign' variants, thereby inflating prevalence estimates. Online databases were searched for all FD screening studies in high-risk clinics (1995-2017). Studies reporting <i>GLA</i> mutations were re-analysed for pathogenic mutations, sex and phenotype. Phenotype-specific and sex-specific prevalence rates were determined. Of 67 studies, 63 that screened 51363patients (33943M and 17420F) and provided <i>GLA</i> mutations were reanalysed for disease-causing mutations. Of reported <i>GLA</i> mutations, benign variants occurred in 47.9% of males and 74.1% of females. The following were the revised prevalence estimates: among 36820 (23954M and 12866F) haemodialysis screenees, 0.21% males and 0.15% females; among 3074 (2031M and 1043F) renal transplant screenees, 0.25% males and no females; among 5491 (4054M and 1437F) cardiac screenees, 0.94% males and 0.90% females; and among 5978 (3904M and 2074F) stroke screenees, 0.13% males and 0.14% females. Among male and female screenees with pathogenic mutations, the type 1 Classic phenotype was predominant (~60%), except more male cardiac patients (75%) had type 2 Later-Onset phenotype. Compared with previous findings, reanalysis of 63 studies increased the screenee numbers (~3.4-fold), eliminated 20 benign/likely benign variants, and provided more accurate sex-specific and phenotype-specific prevalence estimates, ranging from ~0.13% of stroke to ~0.9% of cardiac male or female screenees.