The prevalence of Fabry disease in a statewide chronic kidney disease cohort - Outcomes of the aCQuiRE (Ckd.Qld fabRy Epidemiology) study.

BACKGROUND: Prevalence of Fabry disease amongst Chronic Kidney Disease (CKD) patients on haemodialysis has been shown to be approximately 0.2%. METHODS: We undertook a cross-sectional study employing a cascade screening strategy for Fabry Disease amongst 3000 adult, male and female patients affected by CKD stage 1-5D/T at public, specialty renal practices within participating Queensland Hospital and Health Services from October 2017 to August 2019. A multi-tiered FD screening strategy, utilising a combination of dried blood spot (DBS) enzymatic testing, and if low, then lyso-GB3 testing and DNA sequencing, was used. RESULTS: Mean (SD) age was 64.0 (15.8) years (n = 2992), and 57.9% were male. Eight participants withrew out of the 3000 who consented. Of 2992 screened, 6 (0.20%) received a diagnosis of FD, 2902 (96.99%) did not have FD, and 84 (2.81%) received inconclusive results. Of the patients diagnosed with FD, mean age was 48.5 years; 5 were male (0.29%) and 1 was female (0.08%); 4 were on kidney replacement therapy (2 dialysis and 2 transplant); 3 were new diagnoses. CONCLUSIONS: Estimated overall FD prevalence was 0.20%. Screening of the broader CKD population may be beneficial in identifying cases of FD. TRIAL REGISTRATION: The aCQuiRE Study has been prospectively registered with the Queensland Health Database of Research Activity (DORA, https://dora.health.qld.gov.au ) as pj09946 (Registered 3rd July 2017).

The Ckd. Qld fabRy Epidemiology (aCQuiRE) study protocol: identifying the prevalence of Fabry disease amongst patients with kidney disease in Queensland, Australia.

BACKGROUND: Fabry disease (FD) is a rare, lysosomal storage disorder caused by the absence or deficiency of the enzyme alpha-galactosidase A (α-Gal A) that leads to the abnormal accumulation of the lipid globotriaosylceramide (GB3) in a variety of cell types and tissues throughout the body. FD has an x-linked inheritance pattern. Previously thought to be only carriers, females can also experience FD symptomatology. Symptoms vary in type and severity from patient to patient and tend to increase in severity with age. FD symptoms are non-specific and may be shared with those of other diseases. Misdiagnoses and diagnostic delays are common, often resulting in progressive, irreversible tissue damage. The estimated prevalence of FD in the general population is 1:40,000 to 1:117,000 individuals. However, it is estimated that the prevalence of FD in the dialysis population is 0.12 to 0.7%. Little is known about the prevalence of FD in the broader Chronic Kidney Disease (CKD) population. METHODS: This is an epidemiological study of the prevalence of FD in CKD patents identified from the public renal speciality practices in Queensland, Australia. A cascade approach to screening is being employed with dried blood spot testing for blood levels of alpha-galactosidase A (Alpha-Gal), with follow-up testing for patients with abnormal results by plasma levels of globotriaosylsphingosine (Lyso-GB3) for females and non-definitive cases in males. A diagnosis of FD is confirmed through genetic testing of the GLA gene in cases suspected of having FD based upon Alpha-Gal and Lyso-GB3 testing. DISCUSSION: Expected outcomes of this study include more information about the prevalence of FD at all stages of CKD, including for both males and females. The study may also provide information about common characteristics of FD to assist with diagnosis and optimal management/treatment. Screening is also available for family members of diagnosed patients, with potential for early diagnosis of FD and intervention for those individuals. TRIAL REGISTRATION: Queensland Health Database of Research Activity (DORA, https://dora.health.qld.gov.au) pj09946 (Registered 3rd July 2017).

Sulfatide Analysis by Mass Spectrometry for Screening of Metachromatic Leukodystrophy in Dried Blood and Urine Samples.

BACKGROUND: Metachromatic leukodystrophy (MLD) is an autosomal recessive disorder caused by deficiency in arylsulfatase A activity, leading to accumulation of sulfatide substrates. Diagnostic and monitoring procedures include demonstration of reduced arylsulfatase A activity in peripheral blood leukocytes or detection of sulfatides in urine. However, the development of a screening test is challenging because of instability of the enzyme in dried blood spots (DBS), the widespread occurrence of pseudodeficiency alleles, and the lack of available urine samples from newborn screening programs. METHODS: We measured individual sulfatide profiles in DBS and dried urine spots (DUS) from MLD patients with LC-MS/MS to identify markers with the discriminatory power to differentiate affected individuals from controls. We also developed a method for converting all sulfatide molecular species into a single species, allowing quantification in positive-ion mode upon derivatization. RESULTS: In DBS from MLD patients, we found up to 23.2-fold and 5.1-fold differences in total sulfatide concentrations for early- and late-onset MLD, respectively, compared with controls and pseudodeficiencies. Corresponding DUS revealed up to 164-fold and 78-fold differences for early- and late-onset MLD patient samples compared with controls. The use of sulfatides converted to a single species simplified the analysis and increased detection sensitivity in positive-ion mode, providing a second option for sulfatide analysis. CONCLUSIONS: This study of sulfatides in DBS and DUS suggests the feasibility of the mass spectrometry method for newborn screening of MLD and sets the stage for a larger-scale newborn screening pilot study.

Demographic changes in Australia's regulated health professions: 6-year trends.

Objective Studies of Australian health workforce demographics tend to be limited to single professions, a set geographic area, or based on incomplete data. This study aims to comprehensively describe changes to the demographic characteristics of Australia's regulated health professions over 6 years. Methods Data were sourced from the Australian Health Practitioner Regulation Agency (Ahpra) registration database, and a retrospective analysis of 15 of the 16 regulated health professions between 1 July 2015 and 30 June 2021 was conducted. Variables including profession, age, gender and state/territory locations for the practitioners' principal places of practice were analysed descriptively and via appropriate statistical tests. Results Changes in age, gender representation, and place of practice varied significantly and in different ways across the 15 professions. The total number of registered health practitioners increased by 141 161 (22%) from 2016 to 2021. The number of registered health practitioners per 100 000 population increased by 14% from 2016, with considerable variation across the professions. In 2021, women accounted for 76.3% of health practitioners across the 15 health professions, a significant increase of 0.5% points since 2016. Conclusions Changes to demographics, especially in ageing workforces and feminising professions, can have implications for workforce planning and sustainability. Future research could build on this demographic trend data by investigating causes or undertaking workforce supply or demand modelling.

Prevalence of Fabry disease in dialysis patients: Western Australia Fabry disease screening study - the FoRWARD study.

AIM: To determine the prevalence of undiagnosed Fabry Disease (FD) in Western Australian (WA) patients undergoing dialysis. BACKGROUND: FD is a multisystem X-linked lysosomal storage disease caused by deficient activity of alpha-galactosidase-A (α-GAL-A). Affected individuals are at risk of developing small-fibre neuropathy, rash, progressive kidney disease, hypertrophic cardiomyopathy and ischaemic stroke. Diagnosis is often delayed by years or even decades. Screening high risk population such as dialysis patients may identify patients with undiagnosed Fabry disease. METHODS: A cross-sectional study was undertaken of all adult patients receiving dialysis in WA, without previously known FD. After informed consent they were screened for α-GAL-A activity by dried blood spot samples. Low or inconclusive activity were repeated via Centogene in Rostock, Germany with GLA genetic analysis. Ethics approval was granted by Royal Perth Hospital Human Research Ethic Committee REG 14-136; site-specific approval was granted from appropriate authorities; ANZ Clinical Trials Registry U1111-1163-7629. RESULTS: Between February 2015 & September 2017, α-GAL-A activity was performed on 526 patients at 16 dialysis sites. Twenty-nine patients had initial low α-GAL-A; repeat testing & GLA genotyping showed no confirmed FD cases. The causes of false positive rates were thought to be secondary to impaired protein synthesis due to patient malnutrition and chronic inflammation, which is common among dialysis patients, in addition to poor sampling handling. CONCLUSION: Analysis of this dialysis population has shown a prevalence of 0% undiagnosed FD. False positives results may occur through impaired protein synthesis and sample handling.

Rapid, single-phase extraction of glucosylsphingosine from plasma: A universal screening and monitoring tool.

BACKGROUND: Glucosylsphingosine (GluSph) has emerged as a biomarker for the inherited metabolic disorder, Gaucher disease (GD). We developed a simple laboratory test to measure plasma GluSph and show that elevated GluSph is diagnostic for GD as well as informing on disease burden for monitoring patients on treatment. METHODS: GluSph was measured from a single-phase total lipid extraction of 0.01 mL of plasma by liquid chromatography-electrospray ionisation-tandem mass spectrometry and concentrations extrapolated from a seven point standard curve (0.04 to 20 pmoL). A total of 1464 samples were tested and longitudinal assessment of an additional 20 GD patients. RESULTS: All patients with GD had elevated GluSph compared to unaffected controls and 16 other metabolic disorders. GluSph was also slightly elevated in three patients with Krabbe disease but not at concentrations to confuse a GD diagnosis. GluSph correlated with chitotriosidase in the majority of GD patients on treatment who were informative for this marker. CONCLUSIONS: GluSph can be easily measured from 0.01 mL of plasma and is useful as a diagnostic marker for GD with the current platform suited to high-throughput screening. It outperforms other GD biomarkers for biochemical monitoring of patients receiving enzyme replacement therapy for all individuals.