Clinical course and pathological findings of two late-onset Fabry hemizygous patients including mulberry cell counts after enzyme replacement therapy

Fabry disease is an X-linked inherited lysosomal storage disorder caused by a deficiency of α-galactosidase A activity, resulting in the intracellular accumulation of globotriaosylceramide and related glycosphingolipids. The phenotypes of Fabry disease in both males and females are grouped into two categories: the classical type and the late-onset type. The classical type shows general symptoms including angiokeratoma(s), acroparesthesia, hypohidrosis, corneal opacity, and gastrointestinal symptoms from an early age. The late-onset type shows cardiac or renal (or both) symptoms from a late age. We present herein the clinical course and pathological findings of two late-onset hemizygous Fabry patients after the initiation of enzyme replacement therapy (ERT), along with their mulberry cell counts during treatment. One patient’s case was a renal-variant type without general symptoms; he showed stable renal function and mild proteinuria but little histological improvement with no change in the mulberry cell count during ERT. The other patient had a cardiac-variant type with renal pathological abnormality. He achieved a mild improvement of renal pathological findings, and his mulberry cell count gradually decreased during the treatment. These findings indicate that monitoring the mulberry cell count might help assess the efficacy of ERT, as a renal pathology tool.