FDrisk: development of a validated risk assessment tool for Fabry disease utilizing electronic health record data.

Purpose: Fabry disease (FD) is a rare, X-linked, lysosomal storage disease characterized by great variability in clinical presentation and progressive multisystemic organ damage. Lack of awareness of FD and frequent misdiagnoses cause long diagnostic delays. To address the urgent need for earlier diagnosis, we created an online, risk-assessment scoring tool, the FDrisk, for predicting an individual's risk for FD and prompting diagnostic testing and clinical evaluation. Methods: Utilizing electronic health records, data were collected retrospectively from randomly selected, deidentified patients with FD treated at the Emory Lysosomal Storage Disease Center. Deidentified, negative controls were randomly selected from the Fabry Disease Diagnostic Testing and Education project database, a program within the American Association of Kidney Patients Center for Patient Education and Research. Diagnosis of FD was documented by evidence of a pathogenic variant in GLA and/or an abnormal level of leukocyte α-Gal A. Thirty characteristic clinical features of FD were initially identified and subsequently curated into 16 clinical covariates used as predictors for the risk of FD. An overall prediction model and two sex-specific prediction models were built. Two-hundred and sixty samples (130 cases, 130 controls) were used to train the risk prediction models. One-hundred and ninety-seven independent samples (30 cases, 167 controls) were used for testing model performance. Prediction accuracy was evaluated using a threshold of 0.5 to determine a predicted case vs. control. Results: The overall risk prediction model demonstrated 80% sensitivity, 83.8% specificity, and positive predictive value of 47.1%. The male model demonstrated 75% sensitivity, 95.8% specificity, and positive predictive value of 75%. The female model demonstrated 83.3% sensitivity, 81.3% specificity, and positive predictive value of 45.5%. Patients with risk scores at or above 50% are categorized as "at risk" for FD and should be sent for diagnostic testing. Conclusion: We have developed a statistical risk prediction model, the FDrisk, a validated, clinician-friendly, online, risk-assessment scoring tool for predicting an individual's risk for FD and prompting diagnostic testing and clinical evaluation. As an easily accessible, user-friendly scoring tool, we believe implementing the FDrisk will significantly decrease the time to diagnosis and allow earlier initiation of FD-specific therapy.

Validation of a suspicion index to identify patients at risk for hereditary angioedema.

Background: Hereditary angioedema (HAE) is a genetic condition characterized by dysregulation of the contact (kallikrein-bradykinin) pathway, leading to recurrent episodes of angioedema. Objective: This project sought to determine whether a suspicion index screening tool using electronic health record (EHR) data can identify patients with an increased likelihood of a diagnosis of HAE. Methods: A suspicion index screening tool for HAE was created and validated by using known patients with HAE from the medical literature as well as positive and negative controls from HAE-focused centers. Through the use of key features of medical and family history, a series of logistic regression models for 5 known genetic causes of HAE were created. Top variables populated the digital suspicion scoring system and were run against deidentified EHR data. Patients at 2 diverse sites were categorized as being at increased, possible, or no increased risk of HAE. Results: Prediction scoring using the strongest 13 variables on the "real-world" EHR-positive control data identified all but 1 patient with C1 inhibitor deficiency and patient with non-C1 inhibitor deficiency without false-positive results. The 2 missed patients had no documented family history of HAE in their EHR. When the prediction scoring variables were expanded to 25, the screening algorithm approached 100% sensitivity and specificity. The 25-variable algorithm run on general population EHR data identified 26 patients at the medical centers as being at increased risk for HAE. Conclusions: These results suggest that development, validation, and implementation of suspicion index screening tools can be useful to aid providers in identifying patients with rare genetic conditions.

Fabry disease and COVID-19: international expert recommendations for management based on real-world experience.

The rapid spread of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 has raised questions about Fabry disease (FD) as an independent risk factor for severe COVID-19 symptoms. Available real-world data on 22 patients from an international group of healthcare providers reveals that most patients with FD experience mild-to-moderate COVID-19 symptoms with an additional complication of Fabry pain crises and transient worsening of kidney function in some cases; however, two patients over the age of 55 years with renal or cardiac disease experienced critical COVID-19 complications. These outcomes support the theory that pre-existent tissue injury and inflammation may predispose patients with more advanced FD to a more severe course of COVID-19, while less advanced FD patients do not appear to be more susceptible than the general population. Given these observed risk factors, it is best to reinforce all recommended safety precautions for individuals with advanced FD. Diagnosis of FD should not preclude providing full therapeutic and organ support as needed for patients with FD and severe or critical COVID-19, although a FD-specific safety profile review should always be conducted prior to initiating COVID-19-specific therapies. Continued specific FD therapy with enzyme replacement therapy, chaperone therapy, dialysis, renin-angiotensin blockers or participation to clinical trials during the pandemic is recommended as FD progression will only increase susceptibility to infection. In order to compile outcome data and inform best practices, an international registry for patients affected by Fabry and infected by COVID-19 should be established.

Phenotypic characteristics of the p.Asn215Ser (p.N215S) GLA mutation in male and female patients with Fabry disease: A multicenter Fabry Registry study.

BACKGROUND: The p.Asn215Ser or p.N215S GLA variant has been associated with late-onset cardiac variant of Fabry disease. METHODS: To expand on the scarce phenotype data, we analyzed natural history data from 125 p.N215S patients (66 females, 59 males) enrolled in the Fabry Registry (NCT00196742) and compared it with data from 401 patients (237 females, 164 males) harboring mutations associated with classic Fabry disease. We evaluated interventricular septum thickness (IVST), left ventricular posterior wall thickness (LVPWT), estimated glomerular filtration rate and severe clinical events. RESULTS: In p.N215S males, mildly abnormal mean IVST and LVPWT values were observed in patients aged 25-34 years, and values gradually increased with advancing age. Mean values were similar to those of classic males. In p.N215S females, these abnormalities occurred primarily in patients aged 55-64 years. Severe clinical events in p.N215S patients were mainly cardiac (males 31%, females 8%) while renal and cerebrovascular events were rare. Renal impairment occurred in 17% of p.N215S males (mostly in patients aged 65-74 years), and rarely in females (3%). CONCLUSION: p.N215S is a disease-causing mutation with severe clinical manifestations found primarily in the heart. Cardiac involvement may become as severe as in classic Fabry patients, especially in males.

The future is now: Technology's impact on the practice of genetic counseling.

Smartphones, artificial intelligence, automation, digital communication, and other types of technology are playing an increasingly important role in our daily lives. It is no surprise that technology is also shaping the practice of medicine, and more specifically the practice of genetic counseling. While digital tools have been part of the practice of medical genetics for decades, such as internet- or CD-ROM-based tools like Online Mendelian Inheritance in Man and Pictures of Standard Syndromes and Undiagnosed Malformations in the 1980s, the potential for emerging tools to change how we practice and the way patients consume information is startling. Technology has the potential to aid in at-risk patient identification, assist in generating a differential diagnosis, improve efficiency in medical history collection and risk assessment, provide educational support for patients, and streamline follow-up. Here we review the historic and current uses of technology in genetic counseling, identify challenges to integration, and propose future applications of technology that can shape the practice of genetic counseling.

The Impact of Fabry Disease on Reproductive Fitness.

Fabry disease (FD) is a pan-ethnic, X-linked, progressive lysosomal storage disorder caused by pathogenic mutations in the GLA gene. Published case reports and abstracts suggest that decreased reproductive fitness may occur in males with FD. In order to understand the impact of FD on reproductive fitness and increase the accuracy of reproductive genetic counseling, this study examines a large, multi-centered population of individuals with FD to determine if males have reduced reproductive fitness. Study data were collected on 376 patients through two, gender-specific surveys distributed across the United States and Canada. The number of biological live-born children among individuals with FD was compared to statistics from the general population. Information was also collected on reduced sperm count, depression, pain, use of assisted reproductive technology, and reproductive choice. On average, females affected by FD had more biological live-born children (1.8) than males affected by FD (1.1). However, males affected by FD had an increased mean number of biological children (1.1) compared to the mean number of biological children fathered by men in the United States (0.9). Sixteen of the 134 males with FD reported oligospermia, which suggests that an infertility work up may be indicated for males having difficulty impregnating their partners. In our large multicenter sample, males and females with FD do not exhibit reduced reproductive fitness; on average they have more biological children than the general population in the United States. This information should assist clinicians in providing accurate reproductive genetic counseling and treatment for individuals with FD.

Machine learning based analytics of micro-MRI trabecular bone microarchitecture and texture in type 1 Gaucher disease.

Type 1 Gaucher disease (GD) is an autosomal recessive lysosomal storage disease, affecting bone metabolism, structure and strength. Current bone assessment methods are not ideal. Semi-quantitative MRI scoring is unreliable, not standardized, and only evaluates bone marrow. DXA BMD is also used but is a limited predictor of bone fragility/fracture risk. Our purpose was to measure trabecular bone microarchitecture, as a biomarker of bone disease severity, in type 1 GD individuals with different GD genotypes and to apply machine learning based analytics to discriminate between GD patients and healthy individuals. Micro-MR imaging of the distal radius was performed on 20 type 1 GD patients and 10 healthy controls (HC). Fifteen stereological and textural measures (STM) were calculated from the MR images. General linear models demonstrated significant differences between GD and HC, and GD genotypes. Stereological measures, main contributors to the first two principal components (PCs), explained ~50% of data variation and were significantly different between males and females. Subsequent PCs textural measures were significantly different between GD patients and HC individuals. Textural measures also significantly differed between GD genotypes, and distinguished between GD patients with normal and pathologic DXA scores. PCA and SVM predictive analyses discriminated between GD and HC with maximum accuracy of 73% and area under ROC curve of 0.79. Trabecular STM differences can be quantified between GD patients and HC, and GD sub-types using micro-MRI and machine learning based analytics. Work is underway to expand this approach to evaluate GD disease burden and treatment efficacy.

The management and treatment of children with Fabry disease: A United States-based perspective.

Fabry disease is an inherited X-linked disorder that presents during childhood in male and female patients. Young patients may initially experience pain, hypohidrosis, and gastrointestinal symptoms. Other manifestations of Fabry disease, such as renal and cardiac disease, manifest later in adolescence or adulthood. In the pediatric population, renal damage is typically subclinical and identifiable only through biopsy. Specialists from the United States with expertise in Fabry disease convened during 2013-2014 in order to develop these consensus guidelines about the management and treatment of children with Fabry disease. The presence of symptoms in boys and girls of any age is an indication to begin therapy. Early treatment before the onset of potentially irreversible vital organ pathology is ideal. Asymptomatic children with Fabry mutations should be followed closely for the development of renal, cardiac, neurological, or gastrointestinal signs, symptoms, or laboratory changes, which would warrant treatment initiation. A comprehensive care plan should be implemented by the treating physicians to guide the management of children with Fabry disease.

Antiproteinuric therapy and Fabry nephropathy: factors associated with preserved kidney function during agalsidase-beta therapy.

BACKGROUND: Nephropathy is an important feature of classical Fabry disease, which results in alpha-galactosidase A deficiency and cellular globotriaosylceramide accumulation. We report the safety and efficacy of antiproteinuric therapy with ACE inhibitors or angiotensin II receptor blockers (ARBs) in a study of classical Fabry patients receiving recombinant agalsidase-beta therapy. METHODS AND DESIGN: The goal was maintenance of urine protein to creatinine ratio (UPCR) <0.5 g/g or a 50% reduction in baseline UPCR for 24 patients at eight study sites. The change in estimated glomerular filtration rate (eGFR) was assessed over 21 months of treatment. RESULTS: 18 out of 24 patients achieved the UPCR goal with eGFR slopes that were significantly better than six patients who did not achieve the UPCR goal (-3.6 (-4.8 to -1.1) versus -7.0 (-9.0 to -5.6) mL/min/1.73 m(2)/year, respectively, p=0.018). Despite achieving the UPCR goal, 67% (12/18 patients) still progressed with an eGFR slope <-2 mL/min/1.73 m(2)/year. Regression analysis showed that increased age at initiation of agalsidase-beta therapy was significantly associated with worsened kidney outcome. Hypotension and hyperkalaemia occurred in seven and eight patients, respectively, which required modification of antiproteinuric therapy but was not associated with serious adverse events. CONCLUSIONS: This study documents the effectiveness of agalsidase-beta (1 mg/kg/2 weeks) and antiproteinuric therapy with ACE inhibitors and/or ARB in patients with severe Fabry nephropathy. Patients had preservation of kidney function if agalsidase-beta treatment was initiated at a younger age, and UPCR maintained at or below 0.5 g/g with antiproteinuric therapy. TRIAL REGISTRATION NUMBER: NCT00446862.

Cognitive function in adults aging with fabry disease: a case-control feasibility study using telephone-based assessments.

We examined the feasibility of recruiting US adults ≥45 years old with Fabry disease (FD) for telephone assessments of cognitive functioning. A case-control design matched each FD participant on age, sex, race, and education to four participants from a population-based study. Fifty-four participants with FD age 46-72 years were matched to 216 controls. Standardized cognitive assessments, quality of life (QOL), and medical histories were obtained by phone, supplemented by objective indices of comorbidities. Normalized scores on six cognitive tasks were calculated. On the individual tasks, scores on list recall and semantic fluency were significantly lower among FD participants (p-values < 0.05), while scores on the other four tasks did not differ. After averaging each participant's normalized scores to form a cognitive composite, we examined group differences in composite scores, before and after adjusting for multiple covariates using generalized estimating equations. The composite scores of FD cases were marginally lower than controls before covariate adjustments (p = 0.08). QOL and mental health variables substantially attenuated this finding (p = 0.75), highlighting the influence of these factors on cognition in FD. Additional adjustment for cardiovascular comorbidities, kidney function, and stroke had negligible impact, despite higher prevalence in the FD sample. Telephone-based cognitive assessment methods are feasible among adults with FD, affording access to a geographically dispersed sample. Although decrements in discrete cognitive domains were observed, the overall cognitive function of older adults with FD was equivalent to that of well-matched controls before and after accounting for multiple confounding variables.

Fabry disease in infancy and early childhood: a systematic literature review.

PURPOSE: Fabry disease is a pan-ethnic, progressive, X-linked genetic disorder that commonly presents in childhood and is caused by deficient activity of the lysosomal enzyme alpha-galactosidaseA (α-gal A). Symptoms of Fabry disease in the pediatric population are well described for patients over five years of age; however, data are limited for infancy and early childhood. The purpose of this article is to delineate the age of detection for specific Fabry symptoms in early childhood. METHODS: A systematic retrospective analysis of PubMed indexed, peer-reviewed publications and case reports in the pediatric Fabry population was performed to review symptoms in patients reported before 5 years of age. RESULTS: The most frequently reported symptom in all age groups under 5 years was acroparesthesias/neuropathic pain, reported in 9 children, ranging in age from 2.0-4.0 years. Also notable is the frequency of gastrointestinal issues reported in 6 children aged 1.0-4.1 years of age. CONCLUSION: This article finds clear evidence that symptoms can occur in early childhood, before age 5 years. Given early presenting symptoms and the ability to monitor these disease hallmarks, a timely referral to a medical geneticist or other specialty clinician experienced in managing children with Fabry disease is strongly indicated.

Fabry disease practice guidelines: recommendations of the National Society of Genetic Counselors.

Identification and comprehensive care of individuals who have Fabry disease (FD) requires a multidisciplinary approach inclusive of genetic testing, test interpretation, genetic counseling, long term disease symptom monitoring, treatment recommendations, and coordination of therapy. The purpose of this document is to provide health care professionals with guidelines for testing, care coordination, identification of psychosocial issues, and to facilitate a better understanding of disease treatment expert recommendations for patients with Fabry disease. These recommendations are the opinions of a multicenter working group of genetic counselors, medical geneticists, and other health professionals with expertise in Fabry disease counseling, as well as representatives/founders of the two United States based Fabry disease patient advocacy groups who are themselves affected by Fabry disease. The recommendations are U.S. Preventive Task Force Class III, and they are based on clinical experience, a review of pertinent English-language articles, and reports of expert committees. This document reviews the genetics of Fabry disease, the indications for genetic testing, interpretation of results, psychosocial considerations, and references to professional and patient resources.

Diagnosis of Fabry disease via analysis of family history.

Fabry disease is an X-linked lysosomal storage condition caused by a deficiency of alpha-galactosidase A. In order to determine the average number of family members who are diagnosed with Fabry disease following the diagnosis of a proband, four lysosomal storage disease centers across the United States reviewed the completed pedigrees of their Fabry disease patients. In addition, data from three Fabry disease families from other centers were submitted by patients directly. The pedigree review found 74 probands (54 males and 20 females) who had 357 diagnosed family members, of which 223 were female (60.5%) and 146 were male (39.5%). Analysis found that, on average, there were five family members diagnosed with Fabry disease for every proband. Now that enzyme replacement therapy (ERT) is available for the treatment of Fabry disease, this finding emphasizes the need for all health care professionals to ensure a detailed pedigree has been constructed for each patient affected by Fabry disease and to encourage testing and evaluation of all at-risk family members.