Histologic examination of the cardiomyopathic patients with IVS4 + 919G > A mutation. (A) Endomyocardial biopsy of patient no. 4, who had not received ERT, showed a diffuse vacuolization (arrows) attributed to the lysosomal Gb3 storage and hypertrophic change of cardiomyocytes with hematoxylin and eosin (H&E) staining. These findings were found in most of the enrolled patients. (B) H&E staining of the endomyocardium showed mild interstitial fibrosis (arrow) only in one patient (no. 10) and showed similar diffuse vacuolization. Toluidine blue staining of the endomyocardium revealed cytoplasmic granular inclusion (arrow), which is consistent with Gb3 accumulation, in patient no. 4 (C) and patient no. 12 (D) who has received ERT for 2 year and 9 months.