Clinical Phenotypes of DMD Exon 51 Skip Equivalent Deletions: A Systematic Review.

BACKGROUND: Eteplirsen, the first FDA-approved RNA-modifying therapy for DMD, is applicable to ∼13% of patients with DMD. Because multiple exonic deletions are amenable to exon 51 skipping, the isoforms resulting from the various exon 51-skipped transcripts may vary in stability, function, and phenotype. OBJECTIVE/METHODS: We conducted a detailed review of dystrophinopathy published literature and unpublished databases to compile phenotypic features of patients with exon 51 "skip-equivalent" deletions. RESULTS: Theoretically, 48 different in-frame transcripts may result from exon 51 skipping. We found sufficient clinical information on 135 patients carrying mutations that would result in production of 11 (23%) of these transcripts, suggesting the remainder have not been identified in vivo. The majority had mild phenotypes: BMD (n = 81) or isolated dilated cardiomyopathy (n = 3). Particularly interesting are the asymptomatic (n = 10) or isolated hyperCKemia (n = 20) patients with deletions of exons 45- 51, 48- 51, 49- 51 and 50- 51. Finally, 16 (12%) had more severe phenotypes described as intermediate (n = 2) or DMD (n = 14), and 6 reports had no definitive phenotype. CONCLUSIONS: This review shows that the majority of exon 51 "skip-equivalent" deletions result in milder (BMD) phenotypes and supports that exon 51 skipping therapy could provide clinical benefit, although we acknowledge that other factors, such as age at treatment initiation or ongoing standard of care, may influence the degree of benefit.

Promoting Health Equity And Eliminating Disparities Through Performance Measurement And Payment.

Current approaches to health care quality have failed to reduce health care disparities. Despite dramatic increases in the use of quality measurement and associated payment policies, there has been no notable implementation of measurement strategies to reduce health disparities. The National Quality Forum developed a road map to demonstrate how measurement and associated policies can contribute to eliminating disparities and promote health equity. Specifically, the road map presents a four-part strategy whose components are identifying and prioritizing areas to reduce health disparities, implementing evidence-based interventions to reduce disparities, investing in the development and use of health equity performance measures, and incentivizing the reduction of health disparities and achievement of health equity. To demonstrate how the road map can be applied, we present an example of how measurement and value-based payment can be used to reduce racial disparities in hypertension among African Americans.

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.

An electronic diary is shown to be more reliable than a paper diary: results from a randomized crossover study in patients with persistent asthma.

OBJECTIVES: Test-retest reliability of an asthma paper diary versus an electronic diary (e-diary) with an integrated peak flow meter was investigated. The equivalence of the two modes was also evaluated. METHODS: Prospective, randomized crossover study design in adolescents (12-17 years) and adults (≥18 years). Key inclusion criteria were persistent asthma, Asthma Control Test (ACT) scores ≥16, use of inhaled corticosteroid with or without long-acting beta-agonist for ≥12 weeks, nocturnal awakenings <2 times in the past week, and activity limitations <1 per week. Participants were randomized to either paper then e-diary or e-diary then paper, to be completed for 14 days each. RESULTS: Forty-seven participants completed all study visits. Weekly percentage of symptom-free days (SFDs) and rescue-free days (RFDs) were calculated. Intraclass correlation coefficients (ICCs) of Week 1 mean SFD and RFD (test) and Week 2 mean SFD and RFD (retest), respectively, were estimated in three groups defined as stable: (i) minimal changes in asthma symptoms, as measured by the global patient reported symptom change question, (ii) less than 15% change (absolute value) in 1 second FEV(1) at adjacent study visits, and (iii) changes in ACT scores less than three points for each mode. SFD demonstrated acceptable ICC (≥0.70) using all three definitions of asthma stability for both modes. CONCLUSION: Acceptable reproducibility of the percentage of RFD (ICC = 0.78) was only observed for the e-diary using the FEV(1) stability criterion. The ICCs for SFD and RFD were acceptable, 0.84 and 0.70, respectively, suggesting better reliability for the e-diary.

Radiological evidence of early cerebral microvascular disease in young children with Fabry disease.

We report on 2 children with Fabry disease who had radiologic evidence of microvascular central nervous system involvement despite the clinical absence of renal, cardiac, or cerebral manifestations. This suggests that treatment with enzyme replacement therapy may be necessary early in the disease to avoid irreversible complications.

Correlation of surrogate markers of Gaucher disease. Implications for long-term follow up of enzyme replacement therapy.

BACKGROUND: The excessive storage of cellular debris in the lysosomal storage disorders triggers a variety of cellular responses. Some of these responses are maladaptative and result in the pathology of these diseases. To some extent, cellular responses are specific to the stored material, which influences the pathophysiology of the disease and results in some of its characteristic features. METHODS: A large body of data has been collected for three biochemical (surrogate) markers of Gaucher Disease: angiotensin converting enzyme (ACE), tartrate-resistant acid phosphatase (TRAP) and chitotriosidase (CHITO) using currently available enzyme analysis. Follow up data was gathered in a group of 18 patients. RESULTS: The three markers are correlated between each other and are useful indicators of the disease progress and its response to enzyme replacement therapy (ERT). Retrospective analysis of clinical records and comparison of chitotriosidase values with the baseline Severity Score Index (SSI) allowed prediction of the response patterns for this marker when long-term ERT (>24 months) was evaluated. CONCLUSIONS: The less severely affected patients are more likely to normalize their chitotriosidase activities after long term ERT.

Fabry disease in genetic counseling practice: recommendations of the National Society of Genetic Counselors.

The objective of this document is to provide health care professionals with recommendations for genetic counseling and testing of individuals with a suspected or confirmed diagnosis of Fabry disease, with a family history of Fabry disease, and those identified as female carriers of 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 an individual with Fabry disease who is a founder of a Fabry disease patient advocacy group in the United States. 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 and interpretation of results, psychosocial considerations, and references for professional and patient resources. These recommendations should not be construed as dictating an exclusive course of management, nor does use of such recommendations guarantee a particular outcome. The professional judgment of a healthcare provider, familiar with the facts and circumstances of a specific case, will always supersede these recommendations.