Background and purpose: The cause of initial ischemic stroke in up to 30% of young patients remains unclear. Fabry disease, due to deficient alpha-galactosidase A (alpha-Gal A) activity, is a vascular endothelial glycosphingolipid storage disease typically presenting in childhood. With advancing age, patients develop renal, cardiac, and cerebrovascular disease and die prematurely. A European study suggested an increased prevalence of unrecognized Fabry disease in patients with cryptogenic stroke. We hypothesized that alpha-Gal A deficiency is a rare cause of initial early-onset ischemic stroke in men.
Methods: The Stroke Prevention in Young Men Study enrolled >550 men (15 to 49 years) with first ischemic stroke in the Baltimore-Washington area in 2004 to 2007. Frozen plasma samples were assayed for alpha-Gal A activity, and DNA from patients with consistently low plasma alpha-Gal A activities were sequenced.
Results: The study sample consisted of 558 men (42% African-American; median age 44 years). Stroke was cryptogenic in 154 men (40% African-American). In 10 patients with low plasma alpha-Gal A activities, DNA sequencing identified alterations in the alpha-Gal A gene in 2 patients. The polymorphism, D313Y, which results in low plasma enzyme activity, but near normal levels of cellular activity was seen in one European-American male. The Fabry disease-causing A143T mutation was seen in an African-American male with cryptogenic stroke (0.18% of all strokes: upper 95% CI=0.53%; 0.65% of cryptogenic strokes: upper 95% CI=1.92%).
Conclusions: In this biracial population, unrecognized Fabry disease is a rare but treatable cause of initial ischemic stroke in young men.