Screening Test of Fabry Disease in Patients with Renal Replacement Therapy in the City of Modena

Abstract

Fabry disease is a rare genetic lysosomal storage disease, inherited in an X-linked manner, characterized by lysosomal deposition of globotriaosylceramide due to deficient activity of the enzyme α-galactosidase A. Because the prevalence of this genetic disorder is unknown in the Emilia Romagna region, we conducted a screening study to assess the prevalence of Fabry disease in the city of Modena, Italy.

Material and Methods

A screening study has been conducted in patients on renal replacement therapy at University Hospital of Modena. Screening tests have been performed using dried blood spot method. Alpha-galactosidase A activity and Lyso-Gb3 levels were evaluated in peripheral blood of all men. In women test based on genetic analysis; Lyso-Gb3 was measured only in patients with mutation of gene GLA.

Results

Screening tests have been performed on 388 subjects: 181 maintenance hemodialysis patients, 166 kidney transplant recipients and 41 peritoneal dialysis patients. About 40% of the patients did not had etiological diagnosis of renal disease. Lyso-Gb3 was more specific test than α- galactosidase A (100% vs. 82.5%) to diagnose Fabry disease. We found two different mutations: c.13 A>G p.(Asn5Asp), a variant likely benign and c.937 G>T p.(Asp313Tyr) a variant of uncertain significance. Both the patients carrying these genetic mutations had no symptoms or medical history compatible with Fabry disease.

Conclusion

Identification of variant of uncertain significance such as c.937G>Tp.(Asp313Tyr) showed the limits of genetic analysis to diagnose an inherit disease. Further studies are need to assess the diagnostic value of Lyso-Gb3 for screening for Fabry disease.

KEYWORDS: Fabry Disease, Screening; Lyso-Gb3; c.13 A>G p. Asn5Asp; c.937 G>T p.(Asp313Tyr); D313Y; α-galactosidase A

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