Publications by authors named "Julie McGaughran"

63 Publications

Investigation of current models of care for genetic heart disease in Australia: A national clinical audit.

Int J Cardiol 2021 Feb 11. Epub 2021 Feb 11.

Genetic Health Queensland, Royal Brisbane and Women's Hospital, Herston, QLD 4029, Australia; School of Medicine, University of Queensland, Brisbane, Australia.

Background: This sub-study of the Australian Genomics Cardiovascular Genetic Disorders Flagship sought to conduct the first nation-wide audit in Australia to establish the current practices across cardiac genetics clinics.

Method: An audit of records of patients with a suspected genetic heart disease (cardiomyopathy, primary arrhythmia, autosomal dominant congenital heart disease) who had a cardiac genetics consultation between 1st January 2016 and 31 July 2018 and were offered a diagnostic genetic test.

Results: This audit included 536 records at multidisciplinary cardiac genetics clinics from 11 public tertiary hospitals across five Australian states. Most genetic consultations occurred in a clinic setting (90%), followed by inpatient (6%) and Telehealth (4%). Queensland had the highest proportion of Telehealth consultations (9% of state total). Sixty-six percent of patients had a clinical diagnosis of a cardiomyopathy, 28% a primary arrhythmia, and 0.7% congenital heart disease. The reason for diagnosis was most commonly as a result of investigations of symptoms (73%). Most patients were referred by a cardiologist (85%), followed by a general practitioner (9%) and most genetic tests were funded by the state Genetic Health Service (73%). Nationally, 29% of genetic tests identified a pathogenic or likely pathogenic gene variant; 32% of cardiomyopathies, 26% of primary arrhythmia syndromes, and 25% of congenital heart disease.

Conclusion: We provide important information describing the current models of care for genetic heart diseases throughout Australia. These baseline data will inform the implementation and impact of whole genome sequencing in the Australian healthcare landscape.
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http://dx.doi.org/10.1016/j.ijcard.2021.02.010DOI Listing
February 2021

Gene selection for the Australian Reproductive Genetic Carrier Screening Project ("Mackenzie's Mission").

Eur J Hum Genet 2021 Jan 16;29(1):79-87. Epub 2020 Jul 16.

Murdoch Children's Research Institute, Parkville, VIC, Australia.

Reproductive genetic carrier screening aims to offer couples information about their chance of having children with certain autosomal recessive and X-linked genetic conditions. We developed a gene list for use in "Mackenzie's Mission", a research project in which 10,000 couples will undergo screening. Criteria for selecting genes were: the condition should be life-limiting or disabling, with childhood onset, such that couples would be likely to take steps to avoid having an affected child; and/or be one for which early diagnosis and intervention would substantially change outcome. Strong evidence for gene-phenotype relationship was required. Candidate genes were identified from OMIM and via review of 23 commercial and published gene lists. Genes were reviewed by 16 clinical geneticists using a standard operating procedure, in a process overseen by a multidisciplinary committee which included clinical geneticists, genetic counselors, an ethicist, a parent of a child with a genetic condition and scientists from diagnostic and research backgrounds. 1300 genes met criteria. Genes associated with non-syndromic deafness and non-syndromic differences of sex development were not included. Our experience has highlighted that gene selection for a carrier screening panel needs to be a dynamic process with ongoing review and refinement.
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http://dx.doi.org/10.1038/s41431-020-0685-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7852568PMC
January 2021

Evolutionary dissection of mtDNA hg H: a susceptibility factor for hypertrophic cardiomyopathy.

Mitochondrial DNA A DNA Mapp Seq Anal 2020 08 30;31(6):238-244. Epub 2020 Jun 30.

Department for Congenital Disorders, Statens Serum Institute, Copenhagen, Denmark.

Mitochondrial DNA (mtDNA) haplogroup (hg) H has been reported as a susceptibility factor for hypertrophic cardiomyopathy (HCM). This was established in genetic association studies, however, the SNP or SNP's that are associated with the increased risk have not been identified. Hg H is the most frequent European mtDNA hg with greater than 80 subhaplogroups (subhgs) each defined by specific SNPs. We tested the hypothesis that the distribution of H subhgs might differ between HCM patients and controls. The subhg H distribution in 55 HCM index cases was compared to that of two Danish mtDNA hg H control groups ( = 170 and = 908, respectively). In the HCM group, H and 12 different H subhgs were found. All these, except subhgs H73, were also found in both control groups. The HCM group was also characterized by a higher proportion of H3 compared to H2. In the HCM group the H3/H2 proportion was 1.7, whereas it was 0.45 and 0.54 in the control groups. This tendency was replicated in an independent group of Hg H HCM index cases ( = 39) from Queensland, Australia, where the H3/H2 ratio was 1.5. In conclusion, the H subhgs distribution differs between HCM cases and controls, but the difference is subtle, and the understanding of the pathogenic significance is hampered by the lack of functional studies on the subhgs of H.
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http://dx.doi.org/10.1080/24701394.2020.1782897DOI Listing
August 2020

Constraint and conservation of paired-type homeodomains predicts the clinical outcome of missense variants of uncertain significance.

Hum Mutat 2020 Aug 2;41(8):1407-1424. Epub 2020 Jun 2.

Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia.

The need to interpret the pathogenicity of novel missense variants of unknown significance identified in the homeodomain of X-chromosome aristaless-related homeobox (ARX) gene prompted us to assess the utility of conservation and constraint across these domains in multiple genes compared to conventional in vitro functional analysis. Pathogenic missense variants clustered in the homeodomain of ARX contribute to intellectual disability (ID) and epilepsy, with and without brain malformation in affected males. Here we report novel c.1112G>A, p.Arg371Gln and c.1150C>T, p.Arg384Cys variants in male patients with ID and severe seizures. The third case of a male patient with a c.1109C>T, p.Ala370Val variant is perhaps the first example of ID and autism spectrum disorder (ASD), without seizures or brain malformation. We compiled data sets of pathogenic variants from ClinVar and presumed benign variation from gnomAD and demonstrated that the high levels of sequence conservation and constraint of benign variation within the homeodomain impacts upon the ability of publicly available in silico prediction tools to accurately discern likely benign from likely pathogenic variants in these data sets. Despite this, considering the inheritance patterns of the genes and disease variants with the conservation and constraint of disease variants affecting the homeodomain in conjunction with current clinical assessments may assist in predicting the pathogenicity of missense variants, particularly for genes with autosomal recessive and X-linked patterns of disease inheritance, such as ARX. In vitro functional analysis demonstrates that the transcriptional activity of all three variants was diminished compared to ARX-Wt. We review the associated phenotypes of the published cases of patients with ARX homeodomain variants and propose expansion of the ARX-related phenotype to include severe ID and ASD without brain malformations or seizures. We propose that the use of the constraint and conservation data in conjunction with consideration of the patient phenotype and inheritance pattern may negate the need for the experimental functional validation currently required to achieve a diagnosis.
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http://dx.doi.org/10.1002/humu.24034DOI Listing
August 2020

Hypertrophic Cardiomyopathy: Challenging the Status Quo?

Heart Lung Circ 2020 Apr 27;29(4):556-565. Epub 2019 Dec 27.

Department of Cardiology, Royal Brisbane and Women's Hospital, Brisbane, Qld, Australia; Faculty of Medicine, University of Queensland, Brisbane, Qld, Australia; Faculty of Science, Health, Education and Engineering, University of Sunshine Coast, Brisbane, Qld, Australia; Faculty of Health, Queensland University of Technology, Brisbane, Qld, Australia. Electronic address:

Hypertrophic cardiomyopathy (HCM) is the most common cardiovascular genetic disorder. While our mechanistic understanding has been informed by elegant gene discovery studies that led to the term "disease of the sarcomere", more recent investigations have challenged the single-gene hypothesis. Multimodality imaging has allowed better phenotyping to facilitate early diagnosis, identify treatable phenocopies, and guide management. While HCM remains an important cause of sudden death, recent studies have reported a substantial cumulative burden of heart failure and atrial fibrillation in middle-aged and older individuals. Nonetheless, improvements in risk stratification have allowed early intervention to transition HCM from being a common cause of sudden death in the young to a treatable chronic disease.
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http://dx.doi.org/10.1016/j.hlc.2019.12.005DOI Listing
April 2020

Expansion of phenotype of DDX3X syndrome: six new cases.

Clin Dysmorphol 2019 Oct;28(4):169-174

University of Newcastle, Callaghan.

Pathogenic variants in DDX3X have recently been identified to be a relatively common cause of intellectual disability in females. In this study, we describe six female probands, from five unrelated families, with five novel heterozygous variants in DDX3X, and the identification of potential germline mosaicism. Consistent features between this cohort and previously described cases include developmental delay or intellectual disability, growth disturbance and movement disorder. Common facial dysmorphism within the cohort include short palpebral fissures, micrognathia, bulbous nasal tip, protruding ears, high arched palate, thin upper vermillion and smooth philtrum. Novel clinical features identified from this cohort include facial dysmorphisms, perinatal complications, valgus feet deformity, lipoatrophy, dystonic episodes, and cutaneous mastocytosis. This case series attempts to expand the phenotype of the DDX3X syndrome; however, it remains heterogeneous. Description of further cases is required to more accurately identify the significance of novel phenotypes within this cohort.
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http://dx.doi.org/10.1097/MCD.0000000000000289DOI Listing
October 2019

Missense Variants in the Histone Acetyltransferase Complex Component Gene TRRAP Cause Autism and Syndromic Intellectual Disability.

Authors:
Benjamin Cogné Sophie Ehresmann Eliane Beauregard-Lacroix Justine Rousseau Thomas Besnard Thomas Garcia Slavé Petrovski Shiri Avni Kirsty McWalter Patrick R Blackburn Stephan J Sanders Kévin Uguen Jacqueline Harris Julie S Cohen Moira Blyth Anna Lehman Jonathan Berg Mindy H Li Usha Kini Shelagh Joss Charlotte von der Lippe Christopher T Gordon Jennifer B Humberson Laurie Robak Daryl A Scott Vernon R Sutton Cara M Skraban Jennifer J Johnston Annapurna Poduri Magnus Nordenskjöld Vandana Shashi Erica H Gerkes Ernie M H F Bongers Christian Gilissen Yuri A Zarate Malin Kvarnung Kevin P Lally Peggy A Kulch Brina Daniels Andres Hernandez-Garcia Nicholas Stong Julie McGaughran Kyle Retterer Kristian Tveten Jennifer Sullivan Madeleine R Geisheker Asbjorg Stray-Pedersen Jennifer M Tarpinian Eric W Klee Julie C Sapp Jacob Zyskind Øystein L Holla Emma Bedoukian Francesca Filippini Anne Guimier Arnaud Picard Øyvind L Busk Jaya Punetha Rolph Pfundt Anna Lindstrand Ann Nordgren Fayth Kalb Megha Desai Ashley Harmon Ebanks Shalini N Jhangiani Tammie Dewan Zeynep H Coban Akdemir Aida Telegrafi Elaine H Zackai Amber Begtrup Xiaofei Song Annick Toutain Ingrid M Wentzensen Sylvie Odent Dominique Bonneau Xénia Latypova Wallid Deb Sylvia Redon Frédéric Bilan Marine Legendre Caitlin Troyer Kerri Whitlock Oana Caluseriu Marine I Murphree Pavel N Pichurin Katherine Agre Ralitza Gavrilova Tuula Rinne Meredith Park Catherine Shain Erin L Heinzen Rui Xiao Jeanne Amiel Stanislas Lyonnet Bertrand Isidor Leslie G Biesecker Dan Lowenstein Jennifer E Posey Anne-Sophie Denommé-Pichon Claude Férec Xiang-Jiao Yang Jill A Rosenfeld Brigitte Gilbert-Dussardier Séverine Audebert-Bellanger Richard Redon Holly A F Stessman Christoffer Nellaker Yaping Yang James R Lupski David B Goldstein Evan E Eichler Francois Bolduc Stéphane Bézieau Sébastien Küry Philippe M Campeau

Am J Hum Genet 2019 03 28;104(3):530-541. Epub 2019 Feb 28.

Centre Hospitalier Universitaire Sainte-Justine Research Centre, University of Montreal, Montreal, QC H3T 1C5, Canada; Department of Pediatrics, University of Montreal, Montreal, QC H3T1J4, Canada. Electronic address:

Acetylation of the lysine residues in histones and other DNA-binding proteins plays a major role in regulation of eukaryotic gene expression. This process is controlled by histone acetyltransferases (HATs/KATs) found in multiprotein complexes that are recruited to chromatin by the scaffolding subunit transformation/transcription domain-associated protein (TRRAP). TRRAP is evolutionarily conserved and is among the top five genes intolerant to missense variation. Through an international collaboration, 17 distinct de novo or apparently de novo variants were identified in TRRAP in 24 individuals. A strong genotype-phenotype correlation was observed with two distinct clinical spectra. The first is a complex, multi-systemic syndrome associated with various malformations of the brain, heart, kidneys, and genitourinary system and characterized by a wide range of intellectual functioning; a number of affected individuals have intellectual disability (ID) and markedly impaired basic life functions. Individuals with this phenotype had missense variants clustering around the c.3127G>A p.(Ala1043Thr) variant identified in five individuals. The second spectrum manifested with autism spectrum disorder (ASD) and/or ID and epilepsy. Facial dysmorphism was seen in both groups and included upslanted palpebral fissures, epicanthus, telecanthus, a wide nasal bridge and ridge, a broad and smooth philtrum, and a thin upper lip. RNA sequencing analysis of skin fibroblasts derived from affected individuals skin fibroblasts showed significant changes in the expression of several genes implicated in neuronal function and ion transport. Thus, we describe here the clinical spectrum associated with TRRAP pathogenic missense variants, and we suggest a genotype-phenotype correlation useful for clinical evaluation of the pathogenicity of the variants.
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http://dx.doi.org/10.1016/j.ajhg.2019.01.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6407527PMC
March 2019

A tyrosine kinase-activating variant Asn666Ser in PDGFRB causes a progeria-like condition in the severe end of Penttinen syndrome.

Eur J Hum Genet 2019 04 20;27(4):574-581. Epub 2018 Dec 20.

Department of Medical Genetics, Haukeland University Hospital, 5021, Bergen, Norway.

Missense variants located to the "molecular brake" in the tyrosine kinase hinge region of platelet-derived growth factor receptor-β, encoded by PFGFRB, can cause Penttinen-type (Val665Ala) and Penttinen-like (Asn666His) premature ageing syndromes, as well as infantile myofibromatosis (Asn666Lys and Pro660Thr). We have found the same de novo PDGFRB c.1997A>G p.(Asn666Ser) variants in two patients with lipodystrophy, acro-osteolysis and severely reduced vision due to corneal neovascularisation, reminiscent of a severe form of Penttinen syndrome with more pronounced connective tissue destruction. In line with this phenotype, patient skin fibroblasts were prone to apoptosis. Both in patient fibroblasts and stably transduced HeLa and HEK293 cells, autophosphorylation of PDGFRβ was observed, as well as increased phosphorylation of downstream signalling proteins such as STAT1, PLCγ1, PTPN11/SHP2-Tyr580 and AKT. Phosphorylation of MAPK3 (ERK1) and PTPN11/SHP2-Tyr542 appeared unaffected. This suggests that this missense change not only weakens tyrosine kinase autoinhibition, but also influences substrate binding, as both PTPN11 tyrosines (Tyr542 and Tyr580) usually are phosphorylated upon PDGFR activation. Imatinib was a strong inhibitor of phosphorylation of all these targets, suggesting an option for precision medicine based treatment.
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http://dx.doi.org/10.1038/s41431-018-0323-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6460636PMC
April 2019

Psychosocial Implications of Living with Catecholaminergic Polymorphic Ventricular Tachycardia in Adulthood.

J Genet Couns 2018 06 23;27(3):549-557. Epub 2017 Sep 23.

Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Locked Bag 6, Newtown, NSW, 2042, Australia.

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare inherited arrhythmogenic disease with a high risk of sudden cardiac death. The impact on health-related quality of life (HR-QoL) and psychosocial outcomes is not known. We sought to provide the first description of HR-QoL and psychosocial wellbeing of adults with CPVT, parents of affected children and at-risk relatives. Participants were recruited through the Australian Genetic Heart Disease Registry and invited to complete a cross-sectional survey comprising a number of validated scales and open-ended questions. Thirty-five participants completed surveys (response rate 65%), including 19 with CPVT, 10 unaffected parents of a child with CPVT, and 7 at-risk relatives (one participant considered patient and parent). Young patients <40 years were significantly more likely to report anxiety (p = 0.04), depression (p = 0.03) and posttraumatic stress symptoms (p = 0.02) compared to older CPVT patients. Further, young patients with an implantable cardioverter defibrillator (ICD) reported significantly worse device-related distress (p = 0.04) and shock anxiety (p = 0.003). Patients with a genetic diagnosis had worse psychological adaptation than those patients without a gene result. Parents perceived their affected children to have poor quality of life across all subdomains compared to healthy age-matched children, however quality of life of parents and at-risk relatives was comparable to population norms. Ongoing psychosocial care is required for young people with CPVT. Those with an ICD and/or undergoing genetic testing may require additional support. The challenges of CPVT management should extend beyond the clinical and genetic aspects of care to incorporate greater psychosocial support, and further reinforces the need for a multidisciplinary approach to care.
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http://dx.doi.org/10.1007/s10897-017-0152-1DOI Listing
June 2018

Position Statement on the Diagnosis and Management of Familial Dilated Cardiomyopathy.

Heart Lung Circ 2017 Nov 7;26(11):1127-1132. Epub 2017 Jun 7.

University of Queensland, Brisbane, Qld, Australia; Department of Cardiology, Royal Brisbane and Women's Hospital, Brisbane, Qld, Australia.

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http://dx.doi.org/10.1016/j.hlc.2017.04.021DOI Listing
November 2017

Impact of the implantable cardioverter defibrillator on confidence to undertake physical activity in inherited heart disease: A cross-sectional study.

Eur J Cardiovasc Nurs 2017 Dec 14;16(8):742-752. Epub 2017 Jun 14.

1 Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Sydney, Australia.

Background: Physical activity is associated with improved quality of life. Patients with an implantable cardioverter defibrillator (ICD) face unique clinical and psychological challenges. Factors such as fear of ICD shock may negatively impact on physical activity, while a sense of protection gained from the ICD may instil confidence to be active.

Aim: We aimed to examine the impact of an ICD on physical activity levels and factors associated with amount of activity.

Methods: Two cross-sectional studies were conducted. Accelerometer data (seven-day) was collected in March-November 2015 for 63 consecutively recruited hypertrophic cardiomyopathy patients, with or without an ICD, aged ⩾18 years. A survey study was conducted in July-August 2016 of 155 individuals aged ⩾18 years with an inherited heart disease and an ICD in situ.

Results: Based on the International Physical Activity Questionnaire, mean leisure time physical activity was 239 ± 300 min/week with 51% meeting physical activity guidelines. Accelerometry showed that mean moderate-vigorous physical activity was the same for patients with and without an ICD (254 ± 139 min/week versus 300 ± 150 min/week, p=0.23). Nearly half of survey participants ( n=73) said their device made them more confident to exercise. Being anxious about ICD shocks was the only factor associated with not meeting physical activity guidelines.

Conclusions: Patients with inherited heart disease adjust differently to their ICD device, and for many it has no impact on physical activity. Discussion regarding the appropriate level of physical activity and potential barriers will ensure best possible outcomes in this unique patient group.
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http://dx.doi.org/10.1177/1474515117715760DOI Listing
December 2017

KBG syndrome: An Australian experience.

Am J Med Genet A 2017 Jul 27;173(7):1866-1877. Epub 2017 Apr 27.

Hunter Genetics, Waratah, NSW, Australia.

In 2011, heterozygous mutations in the ANKRD11 gene were identified in patients with KBG syndrome. Since then, 100 cases have been described with the expansion of the clinical phenotype. Here we present 18 KBG affected individuals from 13 unrelated families, 16 with pathogenic mutations in the ANKRD11 gene. Consistent features included intellectual disability, macrodontia, and the characteristic broad forehead with hypertelorism, and a prominent nasal bridge. Common features included hand anomalies, cryptorchidism, and a large number of palate abnormalities. Distinctive findings in this series included malrotation of the abdominal viscera, bilateral inguinal herniae in two patients, basal ganglia calcification and the finding of osteopenia in three patients. Nine novel heterozygous variants were found and the genotype-phenotype correlation was explored. This report highlights the need for thorough examination and investigation of the dental and skeletal systems. The results confirm the specificity of ANKRD11 mutations in KBG and further evidence for this transcription repressor in neural, cardiac, and skeletal development. The description of further cases of KBG syndrome is needed to further delineate this condition, in particular the specific neurological and behavioral phenotype.
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http://dx.doi.org/10.1002/ajmg.a.38121DOI Listing
July 2017

Overlapping SETBP1 gain-of-function mutations in Schinzel-Giedion syndrome and hematologic malignancies.

PLoS Genet 2017 03 27;13(3):e1006683. Epub 2017 Mar 27.

Department of Human Genetics, Radboud Institute of Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.

Schinzel-Giedion syndrome (SGS) is a rare developmental disorder characterized by multiple malformations, severe neurological alterations and increased risk of malignancy. SGS is caused by de novo germline mutations clustering to a 12bp hotspot in exon 4 of SETBP1. Mutations in this hotspot disrupt a degron, a signal for the regulation of protein degradation, and lead to the accumulation of SETBP1 protein. Overlapping SETBP1 hotspot mutations have been observed recurrently as somatic events in leukemia. We collected clinical information of 47 SGS patients (including 26 novel cases) with germline SETBP1 mutations and of four individuals with a milder phenotype caused by de novo germline mutations adjacent to the SETBP1 hotspot. Different mutations within and around the SETBP1 hotspot have varying effects on SETBP1 stability and protein levels in vitro and in in silico modeling. Substitutions in SETBP1 residue I871 result in a weak increase in protein levels and mutations affecting this residue are significantly more frequent in SGS than in leukemia. On the other hand, substitutions in residue D868 lead to the largest increase in protein levels. Individuals with germline mutations affecting D868 have enhanced cell proliferation in vitro and higher incidence of cancer compared to patients with other germline SETBP1 mutations. Our findings substantiate that, despite their overlap, somatic SETBP1 mutations driving malignancy are more disruptive to the degron than germline SETBP1 mutations causing SGS. Additionally, this suggests that the functional threshold for the development of cancer driven by the disruption of the SETBP1 degron is higher than for the alteration in prenatal development in SGS. Drawing on previous studies of somatic SETBP1 mutations in leukemia, our results reveal a genotype-phenotype correlation in germline SETBP1 mutations spanning a molecular, cellular and clinical phenotype.
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http://dx.doi.org/10.1371/journal.pgen.1006683DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5386295PMC
March 2017

Clinical and genetic features of Australian families with long QT syndrome: A registry-based study.

J Arrhythm 2016 Dec 15;32(6):456-461. Epub 2016 Mar 15.

Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Sydney, Australia; School of Medicine, University of Sydney, Sydney, Australia; Department of Cardiology, Royal Prince Alfred Hospital, Sydney, Australia.

Background: Familial long QT syndrome (LQTS) is a primary arrhythmogenic disorder caused by mutations in ion channel genes. The phenotype ranges from asymptomatic individuals to sudden cardiac arrest and death. LQTS is a rare but significant health problem for which global data should exist. This study sought to provide the first clinical and genetic description of Australian families with LQTS.

Methods: We performed a cross-sectional study to evaluate clinical and genetic features of families with LQTS. We recruited individuals from the Australian Genetic Heart Disease Registry and Genetic Heart Disease Clinic, in Sydney, Australia, and included those with a diagnosis of LQTS according to the most recent consensus statement.

Results: Among 108 families with LQTS, 173 individuals were affected. Twenty-five (32%) probands had a sudden cardiac death (SCD) event (including appropriate implantable cardioverter defibrillator [ICD] therapy, or resuscitated cardiac arrest). There were 64 (82%) probands who underwent genetic testing, and 34 (53%) had a pathogenic or likely pathogenic mutation in. Having a family history of LQTS was significantly associated with identification of a pathogenic result (79% versus 14%, <0.0001). There were 16 (9%) participants who experienced delay to diagnosis of at least 12 months.

Conclusions: This is the first clinical and genetic study in a large cohort of Australian families with LQTS. Findings from this study suggest that the clinical and genetic features in this population are not dissimilar to those described in North American, European, and Asian cohorts. Global-scale information about families with LQTS is an important initiative to ensure diagnostic and management approaches are applicable to different populations and ethnicities.
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http://dx.doi.org/10.1016/j.joa.2016.02.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5129121PMC
December 2016

Expanding the genotypic spectrum of CCBE1 mutations in Hennekam syndrome.

Am J Med Genet A 2016 10 27;170(10):2694-7. Epub 2016 Jun 27.

Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia.

Hennekam lymphangiectasia-lymphedema syndrome is an autosomal recessive disorder, with 25% of patients having mutations in CCBE1. We identified a family with two brothers presenting with primary lymphedema, and performed exome sequencing to determine the cause of their disease. Analysis of four family members showed that both affected brothers had the same rare compound heterozygous mutations in CCBE1. The presumed paternally inherited NM_133459.3:c.310G>A; p.(Asp104Asn), lies adjacent to other known pathogenic CCBE1 mutations, while the maternally inherited NM_133459.3:c.80T>C; p.(Leu27Pro) lies in the CCBE1 signal peptide, which has not previously been associated with disease. Functional analysis in a zebrafish model of lymphatic disease showed that both mutations lead to CCBE1 loss of function, confirming the pathogenicity of these variants and expanding the genotypic spectrum of lymphatic disorders. © 2016 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/ajmg.a.37803DOI Listing
October 2016

A Prospective Study of Sudden Cardiac Death among Children and Young Adults.

N Engl J Med 2016 Jun;374(25):2441-52

From the Agnes Ginges Center for Molecular Cardiology, Centenary Institute, University of Sydney (R.D.B., J.I., L.Y., L.L., C.S.), Sydney Medical School, University of Sydney (R.D.B., J.I., J.D., R.P., C.S.), Department of Forensic Medicine, NSW Health Pathology (J.D.), and Department of Cardiology, Royal Prince Alfred Hospital (J.I., L.Y., R.P., C.S.), Sydney, the Department of Cardiology, Royal Children's Hospital, Murdoch Children's Research Institute and University of Melbourne (R.G.W., A.M.D., V.C., D.S.), Departments of Pediatrics (A.M.D.) and Pathology (P.J.), University of Melbourne, Genetic Medicine, Royal Melbourne Hospital (T.T., P.J., J.V., I.W.), Department of Medicine, Royal Melbourne Hospital, University of Melbourne (J.V., I.W.), and Victorian Institute of Forensic Medicine (M.L., N.M.), Melbourne, VIC, Forensic and Scientific Services, Archerfield, QL (J.W., C.N.), University of Queensland (J.W., C.N.), and Royal Brisbane and Women's Hospital (J.A., J.M.), Brisbane, QL, Department of Forensic Pathology, PathWest, Fremantle, WA (J.W.), ACT Pathology, Canberra Hospital, Canberra, ACT (L.H.), Royal Hobart Hospital, University of Tasmania, Hobart, TAS (C.L.), and the Attorney General's Department, University of Adelaide, Adelaide, SA (N.L.) - all in Australia; and Green Lane Pediatric and Congenital Cardiac Services, Starship Children's Hospital (J.C., J.R.S.), LabPLUS, Auckland City Hospital (D.L.), and the Department of Child Health, University of Auckland (J.R.S.), Auckland, New Zealand.

Background: Sudden cardiac death among children and young adults is a devastating event. We performed a prospective, population-based, clinical and genetic study of sudden cardiac death among children and young adults.

Methods: We prospectively collected clinical, demographic, and autopsy information on all cases of sudden cardiac death among children and young adults 1 to 35 years of age in Australia and New Zealand from 2010 through 2012. In cases that had no cause identified after a comprehensive autopsy that included toxicologic and histologic studies (unexplained sudden cardiac death), at least 59 cardiac genes were analyzed for a clinically relevant cardiac gene mutation.

Results: A total of 490 cases of sudden cardiac death were identified. The annual incidence was 1.3 cases per 100,000 persons 1 to 35 years of age; 72% of the cases involved boys or young men. Persons 31 to 35 years of age had the highest incidence of sudden cardiac death (3.2 cases per 100,000 persons per year), and persons 16 to 20 years of age had the highest incidence of unexplained sudden cardiac death (0.8 cases per 100,000 persons per year). The most common explained causes of sudden cardiac death were coronary artery disease (24% of cases) and inherited cardiomyopathies (16% of cases). Unexplained sudden cardiac death (40% of cases) was the predominant finding among persons in all age groups, except for those 31 to 35 years of age, for whom coronary artery disease was the most common finding. Younger age and death at night were independently associated with unexplained sudden cardiac death as compared with explained sudden cardiac death. A clinically relevant cardiac gene mutation was identified in 31 of 113 cases (27%) of unexplained sudden cardiac death in which genetic testing was performed. During follow-up, a clinical diagnosis of an inherited cardiovascular disease was identified in 13% of the families in which an unexplained sudden cardiac death occurred.

Conclusions: The addition of genetic testing to autopsy investigation substantially increased the identification of a possible cause of sudden cardiac death among children and young adults. (Funded by the National Health and Medical Research Council of Australia and others.).
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http://dx.doi.org/10.1056/NEJMoa1510687DOI Listing
June 2016

A balanced paternal interchromosomal reciprocal insertion between 5q12.1q13.2 and 20p12.3p12.1 resulting in separate genetic conditions in two siblings.

Am J Med Genet A 2016 Jul 9;170(7):1930-3. Epub 2016 May 9.

Genetic Health Queensland, Royal Brisbane and Women's Hospital, Brisbane, Queensland.

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http://dx.doi.org/10.1002/ajmg.a.37689DOI Listing
July 2016

CCC- and WASH-mediated endosomal sorting of LDLR is required for normal clearance of circulating LDL.

Nat Commun 2016 Mar 11;7:10961. Epub 2016 Mar 11.

Department of Pediatrics, Molecular Genetics Section, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.

The low-density lipoprotein receptor (LDLR) plays a pivotal role in clearing atherogenic circulating low-density lipoprotein (LDL) cholesterol. Here we show that the COMMD/CCDC22/CCDC93 (CCC) and the Wiskott-Aldrich syndrome protein and SCAR homologue (WASH) complexes are both crucial for endosomal sorting of LDLR and for its function. We find that patients with X-linked intellectual disability caused by mutations in CCDC22 are hypercholesterolaemic, and that COMMD1-deficient dogs and liver-specific Commd1 knockout mice have elevated plasma LDL cholesterol levels. Furthermore, Commd1 depletion results in mislocalization of LDLR, accompanied by decreased LDL uptake. Increased total plasma cholesterol levels are also seen in hepatic COMMD9-deficient mice. Inactivation of the CCC-associated WASH complex causes LDLR mislocalization, increased lysosomal degradation of LDLR and impaired LDL uptake. Furthermore, a mutation in the WASH component KIAA0196 (strumpellin) is associated with hypercholesterolaemia in humans. Altogether, this study provides valuable insights into the mechanisms regulating cholesterol homeostasis and LDLR trafficking.
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http://dx.doi.org/10.1038/ncomms10961DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4792963PMC
March 2016

A multidisciplinary renal genetics clinic improves patient diagnosis.

Med J Aust 2016 Feb;204(2):58-9

Royal Brisbane and Women's Hospital, Brisbane, QLD.

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http://dx.doi.org/10.5694/mja15.01157DOI Listing
February 2016

Factors influencing uptake of familial long QT syndrome genetic testing.

Am J Med Genet A 2016 Feb 6;170A(2):418-425. Epub 2015 Nov 6.

Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Sydney, New South Wales, Australia.

Ongoing challenges of clinical assessment of long QT syndrome (LQTS) highlight the importance of genetic testing in the diagnosis of asymptomatic at-risk family members. Effective access, uptake, and communication of genetic testing are critical for comprehensive cascade family screening and prevention of disease complications such as sudden cardiac death. The aim of this study was to describe factors influencing uptake of LQTS genetic testing, including those relating to access and family communication. We show those who access genetic testing are overrepresented by the socioeconomically advantaged, and that although overall family communication is good, there are some important barriers to be addressed. There were 75 participants (aged 18 years or more, with a clinical and/or genetic diagnosis of LQTS; response rate 71%) who completed a survey including a number of validated scales; demographics; and questions about access, uptake, and communication. Mean age of participants was 46 ± 16 years, 20 (27%) were males and 60 (80%) had genetic testing with a causative gene mutation in 42 (70%). Overall uptake of cascade testing within families was 60% after 4 years from proband genetic diagnosis. All participants reported at least one first-degree relative had been informed of their risk, whereas six (10%) reported at least one first-degree relative had not been informed. Those who were anxious or depressed were more likely to perceive barriers to communicating. Genetic testing is a key aspect of care in LQTS families and intervention strategies that aim to improve equity in access and facilitate effective family communication are needed.
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http://dx.doi.org/10.1002/ajmg.a.37455DOI Listing
February 2016

A protocol for the identification and validation of novel genetic causes of kidney disease.

BMC Nephrol 2015 Sep 15;16:152. Epub 2015 Sep 15.

Institute for Molecular Bioscience, The University of Queensland, St Lucia, Australia.

Background: Genetic renal diseases (GRD) are a heterogeneous and incompletely understood group of disorders accounting for approximately 10 % of those diagnosed with kidney disease. The advent of Next Generation sequencing and new approaches to disease modelling may allow the identification and validation of novel genetic variants in patients with previously incompletely explained or understood GRD.

Methods/design: This study will recruit participants in families/trios from a multidisciplinary sub-specialty Renal Genetics Clinic where known genetic causes of GRD have been excluded or where genetic testing is not available. After informed patient consent, whole exome and/or genome sequencing will be performed with bioinformatics analysis undertaken using a customised variant assessment tool. A rigorous process for participant data management will be undertaken. Novel genetic findings will be validated using patient-derived induced pluripotent stem cells via differentiation to renal and relevant extra-renal tissue phenotypes in vitro. A process for managing the risk of incidental findings and the return of study results to participants has been developed.

Discussion: This investigator-initiated approach brings together experts in nephrology, clinical and molecular genetics, pathology and developmental biology to discover and validate novel genetic causes for patients in Australia affected by GRD without a known genetic aetiology or pathobiology.
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http://dx.doi.org/10.1186/s12882-015-0148-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4570515PMC
September 2015

The Koolen-de Vries syndrome: a phenotypic comparison of patients with a 17q21.31 microdeletion versus a KANSL1 sequence variant.

Eur J Hum Genet 2016 May 26;24(5):652-9. Epub 2015 Aug 26.

Department of Human Genetics, Radboud Institute for Molecular Life Sciences and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.

The Koolen-de Vries syndrome (KdVS; OMIM #610443), also known as the 17q21.31 microdeletion syndrome, is a clinically heterogeneous disorder characterised by (neonatal) hypotonia, developmental delay, moderate intellectual disability, and characteristic facial dysmorphism. Expressive language development is particularly impaired compared with receptive language or motor skills. Other frequently reported features include social and friendly behaviour, epilepsy, musculoskeletal anomalies, congenital heart defects, urogenital malformations, and ectodermal anomalies. The syndrome is caused by a truncating variant in the KAT8 regulatory NSL complex unit 1 (KANSL1) gene or by a 17q21.31 microdeletion encompassing KANSL1. Herein we describe a novel cohort of 45 individuals with KdVS of whom 33 have a 17q21.31 microdeletion and 12 a single-nucleotide variant (SNV) in KANSL1 (19 males, 26 females; age range 7 months to 50 years). We provide guidance about the potential pitfalls in the laboratory testing and emphasise the challenges of KANSL1 variant calling and DNA copy number analysis in the complex 17q21.31 region. Moreover, we present detailed phenotypic information, including neuropsychological features, that contribute to the broad phenotypic spectrum of the syndrome. Comparison of the phenotype of both the microdeletion and SNV patients does not show differences of clinical importance, stressing that haploinsufficiency of KANSL1 is sufficient to cause the full KdVS phenotype.
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http://dx.doi.org/10.1038/ejhg.2015.178DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4930086PMC
May 2016

Antisense-mediated exon skipping: a therapeutic strategy for titin-based dilated cardiomyopathy.

EMBO Mol Med 2015 May;7(5):562-76

I. Medical Department - Cardiology, Klinikum rechts der Isar - Technische Universität München, Munich, Germany DZHK (German Centre for Cardiovascular Research) - partner site Munich Heart Alliance, Munich, Germany

Frameshift mutations in the TTN gene encoding titin are a major cause for inherited forms of dilated cardiomyopathy (DCM), a heart disease characterized by ventricular dilatation, systolic dysfunction, and progressive heart failure. To date, there are no specific treatment options for DCM patients but heart transplantation. Here, we show the beneficial potential of reframing titin transcripts by antisense oligonucleotide (AON)-mediated exon skipping in human and murine models of DCM carrying a previously identified autosomal-dominant frameshift mutation in titin exon 326. Correction of TTN reading frame in patient-specific cardiomyocytes derived from induced pluripotent stem cells rescued defective myofibril assembly and stability and normalized the sarcomeric protein expression. AON treatment in Ttn knock-in mice improved sarcomere formation and contractile performance in homozygous embryos and prevented the development of the DCM phenotype in heterozygous animals. These results demonstrate that disruption of the titin reading frame due to a truncating DCM mutation can be restored by exon skipping in both patient cardiomyocytes in vitro and mouse heart in vivo, indicating RNA-based strategies as a potential treatment option for DCM.
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http://dx.doi.org/10.15252/emmm.201505047DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4492817PMC
May 2015

Further delineation of the KAT6B molecular and phenotypic spectrum.

Eur J Hum Genet 2015 Sep 26;23(9):1165-70. Epub 2014 Nov 26.

Manchester Centre For Genomic Medicine, University of Manchester, St Mary's Hospital, Manchester Academic Health Science Centre, Manchester, UK.

KAT6B sequence variants have been identified previously in both patients with the Say-Barber-Biesecker type of blepharophimosis mental retardation syndromes (SBBS) and in the more severe genitopatellar syndrome (GPS). We report on the findings in a previously unreported group of 57 individuals with suggestive features of SBBS or GPS. Likely causative variants have been identified in 34/57 patients and were commonly located in the terminal exons of KAT6B. Of those where parental samples could be tested, all occurred de novo. Thirty out of thirty-four had truncating variants, one had a missense variant and the remaining three had the same synonymous change predicted to affect splicing. Variants in GPS tended to occur more proximally to those in SBBS patients, and genotype/phenotype analysis demonstrated significant clinical overlap between SBBS and GPS. The de novo synonymous change seen in three patients with features of SBBS occurred more proximally in exon 16. Statistical analysis of clinical features demonstrated that KAT6B variant-positive patients were more likely to display hypotonia, feeding difficulties, long thumbs/great toes and dental, thyroid and patella abnormalities than KAT6B variant-negative patients. The few reported patients with KAT6B haploinsufficiency had a much milder phenotype, though with some features overlapping those of SBBS. We report the findings in a previously unreported patient with a deletion of the KAT6B gene to further delineate the haploinsufficiency phenotype. The molecular mechanisms giving rise to the SBBS and GPS phenotypes are discussed.
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http://dx.doi.org/10.1038/ejhg.2014.248DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4351891PMC
September 2015

Mutations in the voltage-gated potassium channel gene KCNH1 cause Temple-Baraitser syndrome and epilepsy.

Nat Genet 2015 Jan 24;47(1):73-7. Epub 2014 Nov 24.

1] Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia. [2] Department of Integrated Systems Biology, School of Medicine and Health Sciences, George Washington University, Washington, DC, USA. [3] Department of Pediatrics, School of Medicine and Health Sciences, George Washington University, Washington, DC, USA. [4] Illumina, Inc., San Diego, California, USA.

Temple-Baraitser syndrome (TBS) is a multisystem developmental disorder characterized by intellectual disability, epilepsy, and hypoplasia or aplasia of the nails of the thumb and great toe. Here we report damaging de novo mutations in KCNH1 (encoding a protein called ether à go-go, EAG1 or KV10.1), a voltage-gated potassium channel that is predominantly expressed in the central nervous system (CNS), in six individuals with TBS. Characterization of the mutant channels in both Xenopus laevis oocytes and human HEK293T cells showed a decreased threshold of activation and delayed deactivation, demonstrating that TBS-associated KCNH1 mutations lead to deleterious gain of function. Consistent with this result, we find that two mothers of children with TBS, who have epilepsy but are otherwise healthy, are low-level (10% and 27%) mosaic carriers of pathogenic KCNH1 mutations. Consistent with recent reports, this finding demonstrates that the etiology of many unresolved CNS disorders, including epilepsies, might be explained by pathogenic mosaic mutations.
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http://dx.doi.org/10.1038/ng.3153DOI Listing
January 2015

COMMD1 is linked to the WASH complex and regulates endosomal trafficking of the copper transporter ATP7A.

Mol Biol Cell 2015 Jan 29;26(1):91-103. Epub 2014 Oct 29.

Department of Internal Medicine and Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX 75390-9151

COMMD1 deficiency results in defective copper homeostasis, but the mechanism for this has remained elusive. Here we report that COMMD1 is directly linked to early endosomes through its interaction with a protein complex containing CCDC22, CCDC93, and C16orf62. This COMMD/CCDC22/CCDC93 (CCC) complex interacts with the multisubunit WASH complex, an evolutionarily conserved system, which is required for endosomal deposition of F-actin and cargo trafficking in conjunction with the retromer. Interactions between the WASH complex subunit FAM21, and the carboxyl-terminal ends of CCDC22 and CCDC93 are responsible for CCC complex recruitment to endosomes. We show that depletion of CCC complex components leads to lack of copper-dependent movement of the copper transporter ATP7A from endosomes, resulting in intracellular copper accumulation and modest alterations in copper homeostasis in humans with CCDC22 mutations. This work provides a mechanistic explanation for the role of COMMD1 in copper homeostasis and uncovers additional genes involved in the regulation of copper transporter recycling.
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http://dx.doi.org/10.1091/mbc.E14-06-1073DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4279232PMC
January 2015

Delay to diagnosis amongst patients with catecholaminergic polymorphic ventricular tachycardia.

Int J Cardiol 2014 Oct 8;176(3):1402-4. Epub 2014 Aug 8.

Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Newtown, Australia; Sydney Medical School, University of Sydney, Sydney, Australia; Department of Cardiology, Royal Prince Alfred Hospital, Sydney, NSW, Australia. Electronic address:

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http://dx.doi.org/10.1016/j.ijcard.2014.08.020DOI Listing
October 2014

Cardiac myosin-binding protein C gene mutation expressed as hypertrophic cardiomyopathy and left ventricular noncompaction within two families: insights from cardiac magnetic resonance in clinical screening: Camuglia MYBPC3 gene mutation and MRI.

Int J Cardiol 2013 Oct 30;168(3):2950-2. Epub 2013 Apr 30.

Department of Cardiology, Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia; University of Queensland School of Medicine, Brisbane, Queensland, Australia.

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http://dx.doi.org/10.1016/j.ijcard.2013.03.168DOI Listing
October 2013

Clinical predictors of genetic testing outcomes in hypertrophic cardiomyopathy.

Genet Med 2013 Dec 18;15(12):972-7. Epub 2013 Apr 18.

1] Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Sydney, Australia [2] School of Medicine, University of Sydney, Sydney, Australia.

Purpose: Genetic testing for hypertrophic cardiomyopathy has been commercially available for almost a decade; however, low mutation detection rate and cost have hindered uptake. This study sought to identify clinical variables that can predict probands with hypertrophic cardiomyopathy in whom a pathogenic mutation will be identified.

Methods: Probands attending specialized cardiac genetic clinics across Australia over a 10-year period (2002-2011), who met clinical diagnostic criteria for hypertrophic cardiomyopathy and who underwent genetic testing for hypertrophic cardiomyopathy were included. Clinical, family history, and genotype information were collected.

Results: A total of 265 unrelated individuals with hypertrophic cardiomyopathy were included, with 138 (52%) having at least one mutation identified. The mutation detection rate was significantly higher in the probands with hypertrophic cardiomyopathy with an established family history of disease (72 vs. 29%, P < 0.0001), and a positive family history of sudden cardiac death further increased the detection rate (89 vs. 59%, P < 0.0001). Multivariate analysis identified female gender, increased left-ventricular wall thickness, family history of hypertrophic cardiomyopathy, and family history of sudden cardiac death as being associated with greatest chance of identifying a gene mutation. Multiple mutation carriers (n = 16, 6%) were more likely to have suffered an out-of-hospital cardiac arrest or sudden cardiac death (31 vs. 7%, P = 0.012).

Conclusion: Family history is a key clinical predictor of a positive genetic diagnosis and has direct clinical relevance, particularly in the pretest genetic counseling setting.
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http://dx.doi.org/10.1038/gim.2013.44DOI Listing
December 2013