Previously Unidentified Gene Variation Associated with Fabry Disease: The Impact on One Family

Fabry disease is an X-linked lysosomal storage genetic disorder associated with over 1000 mutations in the alpha-galactosidase-A gene region. We report here a 69-year-old male who underwent a kidney biopsy to evaluate progressive renal failure. He was found to have zebra bodies in visceral epithelial cells on biopsy, with electron microscopy showing inclusions within the cytoplasm of multiple podocytes consistent with Fabry disease. An alpha-galactosidase level was found to be 21 nm/hr/mg (normal range 50–150 nm/hr/mg). Genetic studies revealed a missense variant in the GLA gene with alanine replaced by cysteine at position 682 (c.682 A > C, p.N228H) that had not been previously associated with Fabry disease. The same variant was detected in two additional family members. The pathologic findings, clinical features, and low alpha-galactosidase level suggest that the c.682 A > C variant is associated with Fabry disease.

IgA nephropathy suspected to be combined with Fabry disease or Alport syndrome: a case report

Immunoglobulin A (IgA) nephropathy is the most common glomerular disease, and it often manifests as persistent microscopic hematuria or gross hematuria. Fabry disease and Alport syndrome are hereditary diseases caused by mutation of genes, and these diseases are rare in China. At present, patients can be diagnosed with IgA nephropathy by clinical manifestations and laboratory examinations, but there is still controversy about the simultaneous diagnosis of Alport syndrome and Fabry disease in patients with IgA nephropathy. The present case was a 17-year-old girl with hematuria and proteinuria who underwent a renal biopsy. Light microscopy and immunofluorescence showed that IgA was deposited in the mesangium. Under electron microscopy, zebra bodies with a lamellated structure were detected. A gene test showed a COL4A3 gene mutation. The patient was administered prednisone 40 mg once a day and dispersible tablets of mycophenolate mofetil 0.75 g two times a day. The patient’s condition showed a trend of remission. The findings in our case emphasize the importance of renal biopsy and gene detection in hereditary kidney disease, especially for Fabry disease and its rare coexistence with Alport syndrome.

Hydroxychloroquine-induced podocytopathy mimicking Fabry disease

Hydroxychloroquine (HCQ) is largely prescribed as an immunomodulator to prevent systemic diseases flares in patients with systemic lupus erythematous, rheumatoid arthritis, Sjogren’s disease. Among reported side effects, HCQ can accumulate in lysosomes and induced phospholipidosis. Here, we report an HCQ-induced podocytopathy mimicking Fabry disease (FD). They share the same histological lesions: cytoplasmic vacuolisation of the podocytes and zebra bodies on light and electronic microscopy. FD has been ruled out by measuring enzymatic activity and genetic test. The persistence of proteinuria after immunological remission of a systemic disease treated with HCQ could suggest this HCQ-induced podocytopathy.

Feline Mucopolysaccharidosis VII Due to β-glucuronidase Deficiency

A male cat 12–14 weeks old had walking difficulties and an enlarged abdomen. Facial dysmorphism, plump paws, corneal clouding, granulation of neutrophils, vacuolated lymphocytes, and a positive urine test for sulfated glycosaminoglycans suggested mucopolysaccharidosis. Cultured fibroblasts incorporated 35SO4 into mucopolysaccharides more actively than did fibroblasts of a feline control, and degradation was far inferior. Activity of β-glucuronidase was absent in leukocytes and markedly reduced in fibroblasts, thus establishing the diagnosis of mucopolysaccharidosis VII, a disorder previously described in humans, dogs, and mice. Light microscopic examination revealed foam cells in virtually all organs examined, and electron microscopic examination showed pancytic storage of floccular material characteristic of mucopolysaccharides. Stored sphingolipids in the form of zebra bodies were seen in ganglion cells of the central nervous system and in smooth muscle cells of blood vessels. This case represents another animal model of mucopolysaccharidosis VII with the full disease characteristics known in human patients.