Non-invasive high-risk screening for Fabry disease hemizygotes and heterozygotes

Abstract

The most appropriate time for screening for Fabry disease (FD) is school age. For this reason, we developed non-invasive methods for measuring urinary alpha-galactosidase A (alpha-gal A) protein, using enzyme-linked immunosorbent assay (ELISA), and for globotriaosylceramide (GL-3), using tandem mass spectrometry (MS/MS). We measured these two biomarkers in the urine of previously diagnosed FD hemizygotes and heterozygotes, and in controls. All the classic FD hemizygotes were clearly distinguished from controls by either method alone, and combining the two assays produced 96% sensitivity for detecting heterozygotes. To assess the utility of these methods for screening school children and adults at high risk of FD, a pilot study was conducted. To distinguish FD from 432 controls, cut-off values for alpha-gal A protein and GL-3 were set at the 5th and 95th centile values of the controls, respectively. Among the high-risk patients, the measurements exceeded the cut-off values for both biomarkers in male and female subjects and were strong indicators for Fabry hemizygotes and heterozygotes. However, we recommend that if the results of the first measurements exceed the cut-off values for only one of these biomarkers, another urine sample should be requested for re-assay to confirm the result.

A Metabolomic Study To Identify New Globotriaosylceramide-Related Biomarkers in the Plasma of Fabry Disease Patients

“…25 In category 1, one saturated Gb 3 isoform Gb 3 (d18:1)(C16:0) was highly excreted compared to the excretion of all other Gb 3 isoforms with saturated fatty acids, and this is in accordance with the literature. 30 This differs from the Gb 3 profile in the urine of Fabry patients where Gb 3 (d18:1)(C24:0) is the most highly excreted. In category 2, the extent of methylation was greatest for the isoform Gb 3 (d18:1)(C22:0)Me, which is the same as observed in urine.…”

Screening for Fabry disease in high-risk populations: a systematic review

“…Another study using urine spots on filter paper could not detect atypical cardiac variants of FD in men and women,53 and this method does not seem suitable for use in children below the age of 6 months 54. Kitagawa and colleagues measured urinary α-Gal A concentration in combination with urinary Gb-3 concentration and identified all 28 heterozygotes that were studied 55. This approach has not been evaluated in a larger population.…”

Prevalence of Fabry disease in dialysis patients: Japan Fabry disease screening study (J-FAST)

“…We conducted the plasma La-Gal protein measurement by the ELISA method because there is a good correlation between La-Gal protein and a-Gal activity as shown by Kitagawa et al [25]. The patients showing lower values, which were equal to or less than the cutoff value for each measured value, underwent the next examination under suspicion of having Fabry disease.…”