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The purpose of this study was to examine the applicability of the use of samples in dried blood spot (DBS) for the definitive diagnosis of Fabry disease (FD) in males and females and to compare the diagnostic role of α-galactosidase A activity (α-Gal A), levels of lyso-Gb3 and sequencing of the GLA gene in screening patients with suspected FD. Measurement of α-Gal A activity in suspected FD patients in DBS was made followed by lyso-Gb3 determination and GLA gene sequencing. Of the 2381 subjects analyzed, FD was confirmed in 24 patients. Thirteen different variants were considered like pathogenic, five of which had not been previously described (c.143A > G; c.455A > C; c.487G > T; c.554delA; c.1045_1046insA). None of the patients with normal enzyme activity had FD confirmation. The DBS measurement of α-Gal A was more sensitive than lyso-Gb3 levels in both men and women. Definitive diagnosis of FD from a single DBS is possible, allowing samples to be easily sent from anywhere to the reference laboratory.

To assess the utility of globotriaosylsphingosine (lyso-GbA post hoc analysis evaluated data from 97 treatment-naive and enzyme replacement therapy (ERT)-experienced patients with migalastat-amenable GLA variants from FACETS (NCT00925301) and ATTRACT (NCT01218659) and subsequent open-label extension studies. The relationship between plasma lyso-GbNo significant correlations were identified between changes in lyso-GbAlthough used as a pharmacodynamic biomarker in research and clinical studies, plasma lyso-Gb

Purpose Plasma globotriaosylsphingosine (lyso-Gb3) is a promising secondary screening biomarker for Fabry disease. Here, we examined its applicability as a primary screening biomarker for classic and late-onset Fabry disease in males and females. Methods Between 1 July 2014 and 31 December 2015, we screened 2,360 patients (1,324 males) referred from 169 Japanese specialty clinics (cardiology, nephrology, neurology, and pediatrics), based on clinical symptoms suggestive of Fabry disease. We used the plasma lyso-Gb3 concentration, α-galactosidase A (α-Gal A) activity, and analysis of the α-Gal A gene (GLA) for primary and secondary screens, respectively. Results Of 8 males with elevated lyso-Gb3 levels (≥2.0 ng ml–1) and low α-Gal A activity (≤4.0 nmol h–1 ml–1), 7 presented a GLA mutation (2 classic and 5 late-onset). Of 15 females with elevated lyso-Gb3, 7 displayed low α-Gal A activity (5 with GLA mutations; 4 classic and 1 late-onset) and 8 exhibited normal α-Gal A activity (1 with a classic GLA mutation and 3 with genetic variants of uncertain significance). Conclusion Plasma lyso-Gb3 is a potential primary screening biomarker for classic and late-onset Fabry disease probands.

Fabry disease is characterized by lyso-Gb3 accumulation, gastrointestinal symptoms and severe nephropathy and myocardiopathy. Clinically relevant lyso-Gb3 concentrations disrupt the gut microbiota homeostasis. Biofilm formation by enteric bacteria is modulated, favoring Bacteroides fragilis growth. In complex gut bacterial communities, lyso-Gb3 reduced bacteria associated with a healthy microbiota (Bifidobacterium, Akkermansia, Lactobacillus, and butyrate-producing Blautia coccoides-Eubacterium rectale, and Clostridium leptum) and butyrate production. We now discuss the clinical and pathophysiological implications of these findings as butyrate has anti-inflammatory properties through epigenetic regulation of histone acetylation that may protect against nephropathy and myocardiopathy. Lyso-Gb3 modulation of the gut microbiota may directly contribute to the gastrointestinal symptoms and indirectly to systemic manifestations of Fabry disease through modulation of the epigenetic regulation of inflammation., JJAC is funded by an FPI grant from Spanish Ministry of Economics and Competitiveness (BES-2014-069007). The authors were further supported by FIS PI15/00298, PI16/02057, PI18/01366, PI19/00815, DTS18/00032, ERA-PerMed-JTC2018 (KIDNEY ATTACK AC18/00064), ISCIII-RETIC REDinREN RD016/0009 Fondos FEDER, Sociedad Española de Nefrología, Comunidad de Madrid B2017/BMD-3686 CIFRA2-CM, Miguel Servet MS14/00133 to MDSN and AGL2016-75951-R.

Fabry disease is a hereditary, progressive and multisystemic disorder characterized by variable clinical manifestations and a course that can lead to the death of the patient between the fourth and fifth decades of life if not promptly diagnosed. It is a metabolic, lysosomal storage disorder which is due to the functional deficit of the enzyme alpha-galactosidase A (alfa-GAL A). The deficit alters the metabolism of some glycosphingolipids, mainly globotriaosylceramide (Gb3) and lyso-Gb3 (the deacetylated form), causing their storage in lysosomes of various cell types, especially those of the vascular endothelium. The knowledge of this disease has improved in recent years and it is increasingly clear that it could be a more complex disorder than previously thought and that also other factors are likely to be involved in the onset of its symptoms. (aiaf)

Plasma globotriaosylsphingosine (lyso-Gb3) is a promising secondary screening biomarker for Fabry disease. Here, we examined its applicability as a primary screening biomarker for classic and late-onset Fabry disease in males and females.Between 1 July 2014 and 31 December 2015, we screened 2,359 patients (1,324 males) referred from 168 Japanese specialty clinics (cardiology, nephrology, neurology, and pediatrics), based on clinical symptoms suggestive of Fabry disease. We used the plasma lyso-Gb3 concentration, α-galactosidase A (α-Gal A) activity, and analysis of the α-Gal A gene (GLA) for primary and secondary screens, respectively.Of 8 males with elevated lyso-Gb3 levels (≥2.0 ng mlPlasma lyso-Gb3 is a potential primary screening biomarker for classic and late-onset Fabry disease probands.

Biomarkers useful for diagnosis and evaluation of treatment for patients with Fabry disease are urgently needed. Recently, plasma globotriaosylsphingosine (lyso-Gb3) and lyso-Gb3-related analogues have attracted attention as promising biomarkers of Fabry disease. However, the plasma concentrations of lyso-Gb3 and its analogues are extremely low or below the detection limits in some Fabry patients as well as in healthy subjects. In this paper, we introduce the novel application of a nano-liquid chromatography-tandem mass spectrometry (nano-LC-MS/MS) system to the measurement of lyso-Gb3 and its analogues in plasma. Nano-LC-MS/MS requires smaller amounts of samples and is more sensitive than conventional techniques. Using this method, we measured the plasma concentrations of lyso-Gb3 and its analogues in 40 healthy subjects, 5 functional variants (males with E66Q), and various Fabry patients (9 classic Fabry males/9 mutations; 7 later-onset Fabry males/5 mutations; and 10 Fabry females/9 mutations). The results revealed that the mean lyso-Gb3 and lyso-Gb3(-2) concentrations in all the Fabry patient subgroups were statistically higher, especially in the classic Fabry males, than those in the functional variants and healthy subjects. The plasma concentrations of lyso-Gb3 and its analogues in healthy subjects, functional variants, and some Fabry patients with specific mutations (R112H and M296I) that cannot be established by conventional techniques were successfully determined by means of nano-LC-MS/MS. The lyso-Gb3 and lyso-Gb3(-2) concentrations in male patients with these mutations were lower than those in most Fabry patients having other mutations, but higher than those in the functional variants and healthy subjects. This new method is expected to be useful for sensitive determination of the plasma concentrations of lyso-Gb3 and its analogues. This study also revealed that not only lyso-Gb3 but also lyso-Gb3(-2) in plasma is a useful biomarker for the diagnosis of Fabry disease.

The X-chromosomal-linked lysosomal storage disorder Fabry disease can lead to life-threatening manifestations. The pathological significance of the Fabry mutation D313Y is doubted, because, in general, D313Y patients do not present clinical manifestations conformable with Fabry disease. This is in contrast to the analysis of the alpha-galactosidase A activity, which is reduced in D313Y patients. We report a comprehensive clinical, biochemical and molecular genetic analysis of two patients with a D313Y mutation. The alpha-galactosidase A activity was reduced in both patients. No Fabry symptoms or Fabry organ involvement was detected in these patients. The new biomarker lyso-Gb3, severely increased in classical Fabry patients, was determined and in both patients lyso-Gb3 was below the average of a normal population.Our data for the first time not only clinically but also biochemically supports the hypothesis that the D313Y mutation is not a classical one, but a rare variant mutation.