Diagnostic yield from cardiac gene testing for inherited cardiac conditions and re-evaluation of pre-ACMG variants of uncertain significance.

BACKGROUND: Inherited cardiomyopathies (HCM, DCM, ACM) and cardiac ion channelopathies (long QT/Brugada syndromes, CPVT) are associated with significant morbidity and mortality; however, diagnosis of a familial pathogenic variant in a proband allows for subsequent cascade screening of their at-risk relatives. AIMS: We investigated the diagnostic yield from cardiac gene panel testing and reviewed variants of uncertain significance from patients attending three specialist cardiogenetics services in Ireland in the years 2002 to 2020. RESULTS: Reviewing molecular genetic diagnostic reports of 834 patients from 820 families, the initial diagnostic yield of pathogenic/likely pathogenic variants was 237/834 patients (28.4%), increasing to 276/834 patients (33.1%) following re-evaluation of cases with variant(s) of uncertain significance. Altogether, 42/85 patients with VUS reviewed (49.4%) had a re-classification that could change their clinical management. Females were more likely to carry pathogenic/likely pathogenic variants than males (139/374, 37.2% vs 137/460, 29.8%, respectively, p = 0.03), and the diagnostic yields were highest in the 0 to < 2 years age group (6/12, 50.0%) and amongst those tested for cardiomyopathy gene panels (13/35, 37.1%). Variants in the MYBPC3/MYH7 (87/109, 79.8%) and KCNQ1/KCNH2 (91/100, 91.0%) genes were the predominant genetic causes for hypertrophic cardiomyopathy and long QT syndrome, respectively. CONCLUSION: Our study highlights the importance of collation and review of pre-ACMG genetic variants to increase diagnostic utility of genetic testing for inherited heart disease. Almost half of patients with pre-ACMG VUS reviewed had their variant re-classified to likely pathogenic/likely benign which resulted in a positive clinical impact for patients and their families.

Genetic counselors and legal recognition: A made-for-Canada approach.

Genetic counseling is a fast-growing profession in Canada. Yet, despite its growth, genetic counseling lacks legal recognition in the majority of Canadian provinces. Legal recognition serves to regulate professions, including genetic counseling, that if not properly regulated, expose the public to the risk of harm. Under Canadian law, there are three models of legal recognition: 1) the constitution of a professional order, 2) inclusion in a professional order, and 3) delegation. This paper explores the practical implications of these different models of legal recognition for genetic counselors. It focuses on the balancing act between protecting the public and the resources required to seek legal recognition under the three different models. With a small number of genetic counselors (n = 484, with 89% found in 4 provinces) compared to other professions, the route toward professional regulation for genetic counselors can be challenging. Though legal recognition occurs at the provincial rather than federal level in Canada, we nonetheless advocate for pan-Canadian discussions that may benefit future pursuits of legal recognition.

Fatal fetal abnormality Irish live-born survival-an observational study.

The aim of the study was to provide accurate information regarding live-born infant survival after diagnosis of fatal fetal anomaly (FFA) to aid decision-making in respect of pregnancy management, and to ascertain the natural history of live-born infants with FFAs via a retrospective analysis of death records (2006-2018), from the National Paediatric Mortality Registry (source Central Statistics Office 2019). Diagnoses and survival times were ascertained from narrative records with further ascertainment and reconciliation of trisomies 13 and 18 cases by review of cytogenetic test records, the National Death Events Register and National Perinatal Epidemiology Centre data. During the study period, termination of pregnancy was not permitted under the Irish Constitution. Patients are live-born babies with fatal fetal anomalies whose deaths were registered in the Republic of Ireland. The main outcome measure was construction of anomaly-specific survival curves, or survival time range and median for those anomalies with rare occurrence. Survival curves for anencephaly, bilateral renal agenesis, thanatophoric dysplasia, trisomy 13, and trisomy 18 show that 90% (n = 95), 93% (n = 60), 100% (n = 14), 37% (n = 92) and 33% (n = 162), respectively, were deceased by 24 h and 98%, 100%, 100%, 73%, and 53%, respectively, by 1 week post-delivery. Survival time range and median were calculated for triploidy (3.5 h-20 days; 10.5 days), whose occurrence was rare. Anhydramnios, craniorachischisis, hydranencephaly and severe hydrocephalus were extremely rare and all deaths were neonatal deaths. Our results provide 13 years of national natural history data of live birth FFA survival. This provides objective information to aid obstetric counselling of couples upon diagnosis of an FFA.

A retrospective review of the contribution of rare diseases to paediatric mortality in Ireland.

AIMS: To ascertain the number of paediatric deaths (0-14 years) with an underlying rare disease in the Republic of Ireland between the years 2006-2016, and to analyse bed usage by a paediatric cohort of rare disease inpatients prior to in-hospital death. BACKGROUND: Rare diseases are often chronically debilitating and sometimes life-threatening diseases, with the majority (69.9%) of rare diseases being of paediatric onset. The Orphanet database contains information on 6172 unique rare diseases. Under-representation of rare diseases in hospital healthcare coding systems leads to a paucity of rare disease epidemiological data required for healthcare planning. Studies have cited variable incidence rates for rare disease, however the burden of rare diseases to healthcare services still remains unclear. This study represents a thorough effort to identify the percentage of child mortality and paediatric bed usage attributable to rare diseases in the Republic of Ireland, thus addressing a major gap in the rare disease field. METHODS: Retrospective analysis of paediatric death registration details for the Republic of Ireland in the 11-year period 2006-2016 from the National Paediatric Mortality Register. Data was subcategorised as Neonatal (0-28 days), Post Neonatal (29 days < 1 year) and older (1-14 years). Bed usage data (ICD-10 code, narrative and usage) of paediatric inpatients who died during hospitalisation from January 2015 to December 2016 was extracted from the National Quality Assurance Improvement System of in-patient data. Orphacodes were assigned to rare disease cases from ICD-10 codes or diagnostic narrative of both datasets. RESULTS: There were 4044 deaths registered from 2006-2016, aged < 15 years, of these 2368 (58.6%) had an underlying rare disease. Stratifying by age group; 55.6% (1140/2050) of neonatal deaths had a rare disease, 57.8% (450/778) post-neonatal, and 64% (778/1216) of children aged 1-14 years. Mortality coding using ICD-10 codes identified 42% of rare disease cases with the remainder identified using death certificate narrative records. Rare disease patients occupied 87% of bed days used by children < 15 years who died during hospitalisation from January 2015 to December 2016. CONCLUSION: Additional routine rare disease coding is necessary to identify rare diseases within Irish healthcare systems to enable better healthcare planning. Rare disease patients are overrepresented in paediatric mortality statistics and in-patient length of stay during hospital admission prior to death.

The role of primary care in management of rare diseases in Ireland.

BACKGROUND: 'Slaintecare' aims to address complex patient care needs in an integrated fashion with an emphasis on patient-centred, patient-empowered community care.Currently there is a lack of knowledge of the impact of rare disease management in primary care and of the information tools required by general practitioners to deliver integrated care for rare disease patients. AIMS: To complete a pilot survey to estimate the general practice clinical workload attributable to selected rare diseases and assess the use of relevant information sources. METHODS: A retrospective cross-sectional survey was carried out of general practice consultations (2013-2017) for patients with 22 commonly recognised rare diseases. RESULTS: Around 31 general practitioners from 10 Irish practices completed information on 171 patients with rare diseases over 3707 consultations. General practice-specific coding systems were inadequate for rare disease patient identification. Over 139 (81.3%) patients were adult, and 32 (18.7%) were children. Management of care was hospital and not primary care based in 63%. Those eligible for state-reimbursed care had a significantly higher median number of consultations (23 consultations, IQR = 13-37, or 5.8 consultations/year) than those who paid privately (10 consultations, IQR = 4-19, or 2.5 consultations/year) (p < 0.005).General practitioners had access to public information resources on rare diseases but few had knowledge of (35.5%), or had ever used (12.9%) Orphanet, the international rare disease information portal. CONCLUSIONS: Both specific rare disease-specific coding and use of the relevant rare disease information sources are lacking in general practice in Ireland.

Estimating cumulative point prevalence of rare diseases: analysis of the Orphanet database.

Rare diseases, an emerging global public health priority, require an evidence-based estimate of the global point prevalence to inform public policy. We used the publicly available epidemiological data in the Orphanet database to calculate such a prevalence estimate. Overall, Orphanet contains information on 6172 unique rare diseases; 71.9% of which are genetic and 69.9% which are exclusively pediatric onset. Global point prevalence was calculated using rare disease prevalence data for predefined geographic regions from the 'Orphanet Epidemiological file' (http://www.orphadata.org/cgi-bin/epidemio.html). Of the 5304 diseases defined by point prevalence, 84.5% of those analysed have a point prevalence of <1/1 000 000. However 77.3-80.7% of the population burden of rare diseases is attributable to the 4.2% (n = 149) diseases in the most common prevalence range (1-5 per 10 000). Consequently national definitions of 'Rare Diseases' (ranging from prevalence of 5 to 80 per 100 000) represent a variable number of rare disease patients despite sharing the majority of rare disease in their scope. Our analysis yields a conservative, evidence-based estimate for the population prevalence of rare diseases of 3.5-5.9%, which equates to 263-446 million persons affected globally at any point in time. This figure is derived from data from 67.6% of the prevalent rare diseases; using the European definition of 5 per 10 000; and excluding rare cancers, infectious diseases, and poisonings. Future registry research and the implementation of rare disease codification in healthcare systems will further refine the estimates.

Catalogue of inherited disorders found among the Irish Traveller population.

Background Irish Travellers are an endogamous, nomadic, ethnic minority population mostly resident on the island of Ireland with smaller populations in Europe and the USA. High levels of consanguinity result in many rare autosomal recessive disorders. Due to founder effects and endogamy, most recessive disorders are caused by specific homozygous mutations unique to this population. Key clinicians and scientists with experience in managing rare disorders seen in this population have developed a de facto advisory service on differential diagnoses to consider when faced with specific clinical scenarios. Objective(s) To catalogue all known inherited disorders found in the Irish Traveller population. Methods We performed detailed literature and database searches to identify relevant publications and the disease mutations of known genetic disorders found in Irish Travellers. Results We identified 104 genetic disorders: 90 inherited in an autosomal recessive manner; 13 autosomal dominant and one a recurring chromosomal duplication. Conclusion We have collated our experience of inherited disorders found in the Irish Traveller population to make it publically available through this publication to facilitate a targeted genetic approach to diagnostics in this ethnic group.

Incidence of Fragile X syndrome in Ireland.

Described as the commonest single gene cause of learning disability internationally, the incidence of Fragile X syndrome (FXS) has never previously been determined in Ireland. The aim of this work was to determine the observed incidence of FXS in the island of Ireland; the Republic of Ireland (ROI) and Northern Ireland (NI) separately and combined. Ascertainment was achieved for a cross-sectional study by a retrospective, clinical and laboratory database review of positive FXS cases, born in either ROI or NI, between years 2000-2009 inclusive. The observed incidence of FXS per 10,000 live births in the island of Ireland in males was 0.94 (95%CI: 0.75-1.13) or ∼1:10,600 and in females was 0.23 (95%CI: 0.14-0.32) or ∼1:43,000. Comparable testing rates for FXS are present in ROI and NI, with on average 1.48% (1.30% in ROI, 1.96% in NI) of live male births and 0.4% (0.35% in ROI, 0.55% in NI) of live female births undergoing analysis which is comparable to other centres internationally. This study demonstrates the observed incidence of FXS in the island of Ireland is (i) approximately half the estimated worldwide incidence in males and is not explained by low levels of testing, and (ii) approximately one quarter the estimated worldwide incidence in females which may be explained by low levels of testing. © 2017 Wiley Periodicals, Inc.

Novel ETHE1 mutation in a carrier couple having prior offspring affected with ethylmalonic encephalopathy: Genetic analysis, clinical management and reproductive outcome.

Ethylmalonic encephalopathy (EE) is an autosomally recessive inherited disorder with a relentlessly progressive decline in neurological function, usually fatal by the age of ten. It is characterised by generalised hypotonia, psychomotor regression, spastic tetraparesis, dystonia, seizures and, eventually, global neurological failure. Approximately 50 reports have been published worldwide describing this devastating disease, most involving patients of Mediterranean or Arab origin. The fundamental defect in EE likely involves the impairment of a mitochondrial sulphur dioxygenase coded by the ETHE1 gene responsible for the catabolism of sulphide, which subsequently accumulates to toxic levels. A diagnosis of EE should initiate careful genetic evaluation and counselling, particularly if the parents intend to have additional offspring. The present report describes the diagnosis of EE in a reproductive endocrinology context, where both members of a non-consanguineous couple were confirmed to be carriers of an identical A↷G mutation. This previously unknown mutation at nucleotide position c.494 resulted in an amino acid substitution, p.Asp165Gly. Although consideration was given to in vitro fertilisation, embryo biopsy and single gene pre-implantation genetic diagnosis, the couple decided to first utilise a less aggressive therapeutic approach with donor sperm insemination. Pregnancy with a low risk of EE was indeed achieved; however, the infant was affected with a different anomaly (hypoplastic left heart). As this case demonstrates, prior to the initiation of fertility therapy, genetic analysis may be used to provide a confirmatory diagnosis when EE is suspected.

Polymorphisms of the Flavin containing monooxygenase 3 (FMO3) gene do not predispose to essential hypertension in Caucasians.

BACKGROUND: The recessive disorder trimethylaminuria is caused by defects in the FMO3 gene, and may be associated with hypertension. We investigated whether common polymorphisms of the FMO3 gene confer an increased risk for elevated blood pressure and/or essential hypertension. METHODS: FMO3 genotypes (E158K, V257M, E308G) were determined in 387 healthy subjects with ambulatory systolic and diastolic blood pressure measurements, and in a cardiovascular disease population of 1649 individuals, 691(41.9%) of whom had a history of hypertension requiring drug treatment. Haplotypes were determined and their distribution noted. RESULTS: There was no statistically significant association found between any of the 4 common haplotypes and daytime systolic blood pressure in the healthy population (p = 0.65). Neither was a statistically significant association found between the 4 common haplotypes and hypertension status among the cardiovascular disease patients (p = 0.80). CONCLUSION: These results suggest that the variants in the FMO3 gene do not predispose to essential hypertension in this population.