Phenotype and genotype characterization and twin association in patients with Anderson-Fabry cardiomyopathy.

Anderson-Fabry disease (FD), an X-linked recessive lysosomal storage disorder caused by a deficiency of α-galactosidase A (α-Gal A) activity, is associated with cardiac manifestations including arrhythmias, valvular abnormalities, and cardiomyopathy. Early initiation of enzyme replacement therapy (ERT) may have the potential to delay the underlying clinical outcomes in patients with FD. Clinical electrocardiogram (ECG) and echocardiography were used to characterize the cardiomyopathy. Diagnosis of FD was performed by measuring the α-Gal A activity in plasma and mutation analysis by direct sequencing using capillary electrophoresis. We identified four adult hemizygous male patients with cardiomyopathy and other symptoms related to FD; two of them were monozygotic twins. In all cases, ECG and echocardiography showed severe left ventricular (LV) hypertrophy. Some years later, all patients showed typical symptoms of FD, including angiokeratomas and neurological, renal, gastrointestinal, and ocular involvement. A deficiency of α-Gal A activity and point mutations in exon 5 of the GLA gene were detected in all patients. ERT (agalsidase-alfa) was administered every other week as a 0.2 mg/kg intravenous infusion over 40 min. In conclusion, these findings highlight the importance of screening middle-aged patients with LV hypertrophy for the early detection of FD, particularly in direct-line relatives such as twins.