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Page 14 of 34 West et al. Rare Dis Orphan Drugs J 2024;3:22 https://dx.doi.org/10.20517/rdodj.2023.61

Figure 5. Electron microscopy showing lamellated lipid deposits in a podocyte, 4,000x.

Foot process effacement in Fabry nephropathy is also frequently present. Early in childhood, this process
may be focal and associated with underlying lamellar bodies . In addition, the presence of lamellar bodies
[93]
and foot process effacement, as well as vascular and glomerular sclerosis, can antedate the development of
microalbuminuria .
[94]

Immunohistochemistry
A monoclonal antibody to Gb3, or CD77, is available, which stains all renal cell types to varying degrees .
[95]

Other staining properties
In frozen sections, fresh or formalin-fixed, the lipid deposits are birefringent, autofluorescent, sudanophilic,
and positive for oil red O, and PAS. The lipid deposits also stain with Luxol fast blue.

Fabry disease subtypes and classification
Two Fabry disease subtypes are identified, classic and late-onset. In the classic version, lipid deposits are in
all renal cell types, whereas in the late-onset, they are mainly present in podocytes, distal tubular epithelial
cells, and vessels, but not endothelial or mesothelial cells. Males, as hemizygotes, will have Fabry disease
affecting all renal cells in contrast to female heterozygotes who are mosaics due to the Lyon hypothesis with
inactivation of one of the X chromosomes in each cell. This mosaicism of the podocyte has been confirmed
in Fabry nephropathy in females .
[96]

The International Study Group of Fabry Nephropathy developed a scoring system of light microscopic
changes that can be used for assessment of prognosis as well as response to treatment .
[97]