Publications by authors named "Peter D Turnpenny"

60 Publications

Disruption of RFX family transcription factors causes autism, attention-deficit/hyperactivity disorder, intellectual disability, and dysregulated behavior.

Genet Med 2021 Mar 3. Epub 2021 Mar 3.

Division of Medical Genetics, Nemours/A.I. DuPont Hospital for Children, Wilmington, DE, USA.

Purpose: We describe a novel neurobehavioral phenotype of autism spectrum disorder (ASD), intellectual disability, and/or attention-deficit/hyperactivity disorder (ADHD) associated with de novo or inherited deleterious variants in members of the RFX family of genes. RFX genes are evolutionarily conserved transcription factors that act as master regulators of central nervous system development and ciliogenesis.

Methods: We assembled a cohort of 38 individuals (from 33 unrelated families) with de novo variants in RFX3, RFX4, and RFX7. We describe their common clinical phenotypes and present bioinformatic analyses of expression patterns and downstream targets of these genes as they relate to other neurodevelopmental risk genes.

Results: These individuals share neurobehavioral features including ASD, intellectual disability, and/or ADHD; other frequent features include hypersensitivity to sensory stimuli and sleep problems. RFX3, RFX4, and RFX7 are strongly expressed in developing and adult human brain, and X-box binding motifs as well as RFX ChIP-seq peaks are enriched in the cis-regulatory regions of known ASD risk genes.

Conclusion: These results establish a likely role of deleterious variation in RFX3, RFX4, and RFX7 in cases of monogenic intellectual disability, ADHD and ASD, and position these genes as potentially critical transcriptional regulators of neurobiological pathways associated with neurodevelopmental disease pathogenesis.
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http://dx.doi.org/10.1038/s41436-021-01114-zDOI Listing
March 2021

SPEN haploinsufficiency causes a neurodevelopmental disorder overlapping proximal 1p36 deletion syndrome with an episignature of X chromosomes in females.

Am J Hum Genet 2021 03 16;108(3):502-516. Epub 2021 Feb 16.

Division of Medical Genetics, Department of Pediatrics, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA 15224, USA.

Deletion 1p36 (del1p36) syndrome is the most common human disorder resulting from a terminal autosomal deletion. This condition is molecularly and clinically heterogeneous. Deletions involving two non-overlapping regions, known as the distal (telomeric) and proximal (centromeric) critical regions, are sufficient to cause the majority of the recurrent clinical features, although with different facial features and dysmorphisms. SPEN encodes a transcriptional repressor commonly deleted in proximal del1p36 syndrome and is located centromeric to the proximal 1p36 critical region. Here, we used clinical data from 34 individuals with truncating variants in SPEN to define a neurodevelopmental disorder presenting with features that overlap considerably with those of proximal del1p36 syndrome. The clinical profile of this disease includes developmental delay/intellectual disability, autism spectrum disorder, anxiety, aggressive behavior, attention deficit disorder, hypotonia, brain and spine anomalies, congenital heart defects, high/narrow palate, facial dysmorphisms, and obesity/increased BMI, especially in females. SPEN also emerges as a relevant gene for del1p36 syndrome by co-expression analyses. Finally, we show that haploinsufficiency of SPEN is associated with a distinctive DNA methylation episignature of the X chromosome in affected females, providing further evidence of a specific contribution of the protein to the epigenetic control of this chromosome, and a paradigm of an X chromosome-specific episignature that classifies syndromic traits. We conclude that SPEN is required for multiple developmental processes and SPEN haploinsufficiency is a major contributor to a disorder associated with deletions centromeric to the previously established 1p36 critical regions.
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http://dx.doi.org/10.1016/j.ajhg.2021.01.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8008487PMC
March 2021

Ectrodactyly-ectodermal dysplasia-clefting syndrome presenting with bilateral choanal atresia and rectal stenosis.

Am J Med Genet A 2020 08 31;182(8):1939-1943. Epub 2020 May 31.

Clinical Genetics, Royal Devon & Exeter NHS Foundation Trust, Exeter, UK.

We present the case of a male who shortly after birth developed acute respiratory distress due to bilateral choanal atresia, following which he was found to have rectal stenosis. Genetic testing for CHARGE syndrome was negative, but whole genome sequencing identified heterozygosity for a pathogenic missense variant in TP63 (c.727C > T, p.(Arg243Trp). He also has partial cutaneous syndactyly of the third and fourth fingers of the right hand, and bilateral lacrimal duct stenosis/aplasia. A later maxillofacial review identified a palpable submucousal cleft and his scalp hair is blond and slightly sparse. Choanal atresia and rectal stenosis are recognized features of ectrodactyly-ectodermal dysplasia-clefting syndrome, but we believe this is the first report of a case presenting with these features in the absence of the cardinal features.
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http://dx.doi.org/10.1002/ajmg.a.61628DOI Listing
August 2020

Clinical findings of 21 previously unreported probands with HNRNPU-related syndrome and comprehensive literature review.

Am J Med Genet A 2020 07 22;182(7):1637-1654. Epub 2020 Apr 22.

Sheffield Clinical Genetics Service, Sheffield Children's NHS Foundation Trust, Sheffield, UK.

With advances in genetic testing and improved access to such advances, whole exome sequencing is becoming a first-line investigation in clinical work-up of children with developmental delay/intellectual disability (ID). As a result, the need to understand the importance of genetic variants and its effect on the clinical phenotype is increasing. Here, we report on the largest cohort of patients with HNRNPU variants. These 21 patients follow on from the previous study published by Yates et al. in 2017 from our group predominantly identified from the Deciphering Developmental Disorders study that reported seven patients with HNRNPU variants. All the probands reported here have a de novo loss-of-function variant. These probands have craniofacial dysmorphic features, in the majority including widely spaced teeth, microcephaly, high arched eyebrows, and palpebral fissure abnormalities. Many of the patients in the group also have moderate to severe ID and seizures that tend to start in early childhood. This series has allowed us to define a novel neurodevelopmental syndrome, with a likely mechanism of haploinsufficiency, and expand substantially on already published literature on HNRNPU-related neurodevelopmental syndrome.
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http://dx.doi.org/10.1002/ajmg.a.61599DOI Listing
July 2020

Amniotic band sequence in paternal half-siblings with vascular Ehlers-Danlos syndrome.

Am J Med Genet A 2020 03 12;182(3):553-556. Epub 2019 Dec 12.

Clinical Genetics, Royal Devon and Exeter NHS Foundation Trust, Exeter, UK.

Familial amniotic band sequence (ABS) is rare but has been reported in the offspring of mothers with connective tissue disorders. We present a family of two half-siblings with ABS who share the same biological father. Following a serious vascular event a de novo pathogenic variant in COL3A1 was detected in the father, confirming a diagnosis of vascular Ehlers-Danlos syndrome (vEDS). The same variant was found in both his ABS-affected children but not in his unaffected child. The amniotic membrane is derived from fetal tissue, type III collagen being a component. As the affected children are paternal half-siblings, ABS was less likely due to maternal factors. Rather, the amniotic bands may have resulted from decreased type III collagen production as seen in people with vEDS, causing fragility of the amniotic membrane. Consequently, it is important to consider vEDS in patients with ABS.
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http://dx.doi.org/10.1002/ajmg.a.61449DOI Listing
March 2020

Delineation of dominant and recessive forms of LZTR1-associated Noonan syndrome.

Clin Genet 2019 06 3;95(6):693-703. Epub 2019 Apr 3.

Oxford Centre for Genomic Medicine, Oxford University Hospitals NHS Foundation Trust, Oxford, UK.

Noonan syndrome (NS) is characterised by distinctive facial features, heart defects, variable degrees of intellectual disability and other phenotypic manifestations. Although the mode of inheritance is typically dominant, recent studies indicate LZTR1 may be associated with both dominant and recessive forms. Seeking to describe the phenotypic characteristics of LZTR1-associated NS, we searched for likely pathogenic variants using two approaches. First, scrutiny of exomes from 9624 patients recruited by the Deciphering Developmental Disorders (DDDs) study uncovered six dominantly-acting mutations (p.R97L; p.Y136C; p.Y136H, p.N145I, p.S244C; p.G248R) of which five arose de novo, and three patients with compound-heterozygous variants (p.R210*/p.V579M; p.R210*/p.D531N; c.1149+1G>T/p.R688C). One patient also had biallelic loss-of-function mutations in NEB, consistent with a composite phenotype. After removing this complex case, analysis of human phenotype ontology terms indicated significant phenotypic similarities (P = 0.0005), supporting a causal role for LZTR1. Second, targeted sequencing of eight unsolved NS-like cases identified biallelic LZTR1 variants in three further subjects (p.W469*/p.Y749C, p.W437*/c.-38T>A and p.A461D/p.I462T). Our study strengthens the association of LZTR1 with NS, with de novo mutations clustering around the KT1-4 domains. Although LZTR1 variants explain ~0.1% of cases across the DDD cohort, the gene is a relatively common cause of unsolved NS cases where recessive inheritance is suspected.
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http://dx.doi.org/10.1111/cge.13533DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6563422PMC
June 2019

Quantifying the contribution of recessive coding variation to developmental disorders.

Science 2018 12 8;362(6419):1161-1164. Epub 2018 Nov 8.

Clinical Genetics, Royal Devon and Exeter NHS Foundation Trust, Exeter, UK.

We estimated the genome-wide contribution of recessive coding variation in 6040 families from the Deciphering Developmental Disorders study. The proportion of cases attributable to recessive coding variants was 3.6% in patients of European ancestry, compared with 50% explained by de novo coding mutations. It was higher (31%) in patients with Pakistani ancestry, owing to elevated autozygosity. Half of this recessive burden is attributable to known genes. We identified two genes not previously associated with recessive developmental disorders, and , and functionally validated them with mouse and cellular models. Our results suggest that recessive coding variants account for a small fraction of currently undiagnosed nonconsanguineous individuals, and that the role of noncoding variants, incomplete penetrance, and polygenic mechanisms need further exploration.
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http://dx.doi.org/10.1126/science.aar6731DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6726470PMC
December 2018

Missense Mutations of the Pro65 Residue of PCGF2 Cause a Recognizable Syndrome Associated with Craniofacial, Neurological, Cardiovascular, and Skeletal Features.

Am J Hum Genet 2018 11 18;103(5):786-793. Epub 2018 Oct 18.

Institute of Medical Genetics, University Hospital of Wales, Cardiff CF14 4XW, UK; Division of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff CF14 4XN, UK. Electronic address:

PCGF2 encodes the polycomb group ring finger 2 protein, a transcriptional repressor involved in cell proliferation, differentiation, and embryogenesis. PCGF2 is a component of the polycomb repressive complex 1 (PRC1), a multiprotein complex which controls gene silencing through histone modification and chromatin remodelling. We report the phenotypic characterization of 13 patients (11 unrelated individuals and a pair of monozygotic twins) with missense mutations in PCGF2. All the mutations affected the same highly conserved proline in PCGF2 and were de novo, excepting maternal mosaicism in one. The patients demonstrated a recognizable facial gestalt, intellectual disability, feeding problems, impaired growth, and a range of brain, cardiovascular, and skeletal abnormalities. Computer structural modeling suggests the substitutions alter an N-terminal loop of PCGF2 critical for histone biding. Mutant PCGF2 may have dominant-negative effects, sequestering PRC1 components into complexes that lack the ability to interact efficiently with histones. These findings demonstrate the important role of PCGF2 in human development and confirm that heterozygous substitutions of the Pro65 residue of PCGF2 cause a recognizable syndrome characterized by distinctive craniofacial, neurological, cardiovascular, and skeletal features.
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http://dx.doi.org/10.1016/j.ajhg.2018.09.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6218713PMC
November 2018

Recontacting patients in clinical genetics services: recommendations of the European Society of Human Genetics.

Eur J Hum Genet 2019 02 11;27(2):169-182. Epub 2018 Oct 11.

Clinical Genetics Department, Guy's & St. Thomas' NHS Foundation Trust, London, UK.

Technological advances have increased the availability of genomic data in research and the clinic. If, over time, interpretation of the significance of the data changes, or new information becomes available, the question arises as to whether recontacting the patient and/or family is indicated. The Public and Professional Policy Committee of the European Society of Human Genetics (ESHG), together with research groups from the UK and the Netherlands, developed recommendations on recontacting which, after public consultation, have been endorsed by ESHG Board. In clinical genetics, recontacting for updating patients with new, clinically significant information related to their diagnosis or previous genetic testing may be justifiable and, where possible, desirable. Consensus about the type of information that should trigger recontacting converges around its clinical and personal utility. The organization of recontacting procedures and policies in current health care systems is challenging. It should be sustainable, commensurate with previously obtained consent, and a shared responsibility between healthcare providers, laboratories, patients, and other stakeholders. Optimal use of the limited clinical resources currently available is needed. Allocation of dedicated resources for recontacting should be considered. Finally, there is a need for more evidence, including economic and utility of information for people, to inform which strategies provide the most cost-effective use of healthcare resources for recontacting.
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http://dx.doi.org/10.1038/s41431-018-0285-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6336881PMC
February 2019

Bi-allelic Mutations in Phe-tRNA Synthetase Associated with a Multi-system Pulmonary Disease Support Non-translational Function.

Am J Hum Genet 2018 07;103(1):100-114

Institute of Human Genetics, Technical University Munich, 81675 Munich, Germany; Institute of Human Genetics, Helmholtz Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH), Ingolstädter Landstr. 1, 85764 Neuherberg, Germany.

The tRNA synthetases catalyze the first step of protein synthesis and have increasingly been studied for their nuclear and extra-cellular ex-translational activities. Human genetic conditions such as Charcot-Marie-Tooth have been attributed to dominant gain-of-function mutations in some tRNA synthetases. Unlike dominantly inherited gain-of-function mutations, recessive loss-of-function mutations can potentially elucidate ex-translational activities. We present here five individuals from four families with a multi-system disease associated with bi-allelic mutations in FARSB that encodes the beta chain of the alphabeta phenylalanine-tRNA synthetase (FARS). Collectively, the mutant alleles encompass a 5'-splice junction non-coding variant (SJV) and six missense variants, one of which is shared by unrelated individuals. The clinical condition is characterized by interstitial lung disease, cerebral aneurysms and brain calcifications, and cirrhosis. For the SJV, we confirmed exon skipping leading to a frameshift associated with noncatalytic activity. While the bi-allelic combination of the SJV with a p.Arg305Gln missense mutation in two individuals led to severe disease, cells from neither the asymptomatic heterozygous carriers nor the compound heterozygous affected individual had any defect in protein synthesis. These results support a disease mechanism independent of tRNA synthetase activities in protein translation and suggest that this FARS activity is essential for normal function in multiple organs.
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http://dx.doi.org/10.1016/j.ajhg.2018.06.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6035289PMC
July 2018

De novo gain-of-function variants in KCNT2 as a novel cause of developmental and epileptic encephalopathy.

Ann Neurol 2018 06;83(6):1198-1204

Institute of Human Genetics, University of Leipzig Hospitals and Clinics, Leipzig, Germany.

Variants in several potassium channel genes have been found in developmental and epileptic encephalopathies (DEE). We report on 2 females with de novo variants in KCNT2 with West syndrome followed by Lennox-Gastaut syndrome or with DEE with migrating focal seizures. After in vitro analysis suggested quinidine-responsive gain-of-function effects, we treated 1 of the girls with quinidine add-on therapy and achieved marked clinical improvements. This suggests that the new spectrum of KCNT2-related disorders do not only share similar phenotypic and in vitro functional and pharmacological features with previously known KCNT1-related disorders, but also represents a further example for possible precision medicine approaches. Ann Neurol 2018;83:1198-1204.
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http://dx.doi.org/10.1002/ana.25248DOI Listing
June 2018

Extending the clinical and genetic spectrum of ARID2 related intellectual disability. A case series of 7 patients.

Eur J Med Genet 2019 Jan 23;62(1):27-34. Epub 2018 Apr 23.

West of Scotland Regional Genetics Service, Laboratory Medicine Building, Queen Elizabeth University Hospital, Glasgow, United Kingdom. Electronic address:

In the last 3 years de novo sequence variants in the ARID2 (AT-rich interaction domain 2) gene, a subunit of the SWI/SNF complex, have been linked to intellectual disabilities in 3 case reports including one which describes frameshift mutations in ARID2 in 2 patients with features resembling Coffin-Siris syndrome. Coffin-Siris syndrome (CSS) is a rare congenital syndrome characterized by intellectual deficit, coarse facial features and hypoplastic or absent fifth fingernails and/or toenails among other features. Mutations in a number of different genes encoding SWI/SNF chromatin remodelling complex proteins have been described but the underlying molecular cause remains unknown in approximately 40% of patients with CSS. Here we describe 7 unrelated individuals, 2 with deletions of the ARID2 region and 5 with de novo truncating mutations in the ARID2 gene. Similarities to CSS are evident. Although hypertrichosis and hypoplasia of the fifth finger nail and distal phalanx do not appear to be common in these patients, toenail hypoplasia and the presence of Wormian bones might support the involvement of ARID2.
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http://dx.doi.org/10.1016/j.ejmg.2018.04.014DOI Listing
January 2019

Recontacting or not recontacting? A survey of current practices in clinical genetics centres in Europe.

Eur J Hum Genet 2018 07 23;26(7):946-954. Epub 2018 Apr 23.

Egenis, University of Exeter, Exeter, UK.

Advances in genomic medicine are improving diagnosis and treatment of some health conditions, and the question of whether former patients should be recontacted is therefore timely. The issue of recontacting is becoming more important with increased integration of genomics in 'mainstream' medicine. Empirical evidence is needed to advance the discussion over whether and how recontacting should be implemented. We administered a web-based survey to genetic services in European countries to collect information about existing infrastructures and practices relevant to recontacting patients. The majority of the centres stated they had recontacted patients to update them about new significant information; however, there were no standardised practices or systems in place. There was also a multiplicity of understandings of the term 'recontacting', which respondents conflated with routine follow-up programmes, or even with post-test counselling. Participants thought that recontacting systems should be implemented to provide the best service to the patients and families. Nevertheless, many barriers to implementation were mentioned. These included: lack of resources and infrastructure, concerns about potential negative psychological consequences of recontacting, unclear operational definitions of recontacting, policies that prevent healthcare professionals from recontacting, and difficulties in locating patients after their last contact. These barriers are also intensified by the highly variable development (and establishment) of the specialties of medical genetics and genetic counselling across different European countries. Future recommendations about recontacting need to consider these barriers. It is also important to reach an 'operational definition' that can be useful in different countries.
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http://dx.doi.org/10.1038/s41431-018-0131-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6018700PMC
July 2018

Summary of the first inaugural joint meeting of the International Consortium for scoliosis genetics and the International Consortium for vertebral anomalies and scoliosis, March 16-18, 2017, Dallas, Texas.

Am J Med Genet A 2018 01 21;176(1):253-256. Epub 2017 Nov 21.

Texas Scottish Rite Hospital for Children, Dallas, Texas.

Scoliosis represents the most common musculoskeletal disorder in children and affects approximately 3% of the world population. Scoliosis is separated into two major phenotypic classifications: congenital and idiopathic. Idiopathic scoliosis is defined as a curvature of the spine of 10° or greater visualized on plane radiograph and does not have associated vertebral malformations (VM). "Congenital" scoliosis (CS) due to malformations in vertebrae is frequently associated with other birth defects. Recently, significant advances have been made in understanding the genetic basis of both conditions. There is evidence that both conditions are etiologically related. A 2-day conference entitled "Genomic Approaches to Understanding and Treating Scoliosis" was held at Scottish Rite Hospital for Children in Dallas, Texas, to synergize research in this field. This first combined, multidisciplinary conference featured international scoliosis researchers in basic and clinical sciences. A major outcome of the conference advancing scoliosis research was the proposal and subsequent vote in favor of merging the International Consortium for Vertebral Anomalies and Scoliosis (ICVAS) and International Consortium for Scoliosis Genetics (ICSG) into a single entity called International Consortium for Spinal Genetics, Development, and Disease (ICSGDD). The ICSGDD is proposed to meet annually as a forum to synergize multidisciplinary spine deformity research.
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http://dx.doi.org/10.1002/ajmg.a.38550DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6525596PMC
January 2018

Diagnosis of lethal or prenatal-onset autosomal recessive disorders by parental exome sequencing.

Prenat Diagn 2018 01 3;38(1):33-43. Epub 2017 Dec 3.

Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Melbourne, Vic, Australia.

Objective: Rare genetic disorders resulting in prenatal or neonatal death are genetically heterogeneous, but testing is often limited by the availability of fetal DNA, leaving couples without a potential prenatal test for future pregnancies. We describe our novel strategy of exome sequencing parental DNA samples to diagnose recessive monogenic disorders in an audit of the first 50 couples referred.

Method: Exome sequencing was carried out in a consecutive series of 50 couples who had 1 or more pregnancies affected with a lethal or prenatal-onset disorder. In all cases, there was insufficient DNA for exome sequencing of the affected fetus. Heterozygous rare variants (MAF < 0.001) in the same gene in both parents were selected for analysis. Likely, disease-causing variants were tested in fetal DNA to confirm co-segregation.

Results: Parental exome analysis identified heterozygous pathogenic (or likely pathogenic) variants in 24 different genes in 26/50 couples (52%). Where 2 or more fetuses were affected, a genetic diagnosis was obtained in 18/29 cases (62%). In most cases, the clinical features were typical of the disorder, but in others, they result from a hypomorphic variant or represent the most severe form of a variable phenotypic spectrum.

Conclusion: We conclude that exome sequencing of parental samples is a powerful strategy with high clinical utility for the genetic diagnosis of lethal or prenatal-onset recessive disorders. © 2017 The Authors Prenatal Diagnosis published by John Wiley & Sons Ltd.
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http://dx.doi.org/10.1002/pd.5175DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5836855PMC
January 2018

Recontacting in clinical practice: the views and expectations of patients in the United Kingdom.

Eur J Hum Genet 2017 10 2;25(10):1106-1112. Epub 2017 Aug 2.

Egenis, University of Exeter, Exeter, UK.

This paper explores the views and expectations of patients concerning recontacting in clinical practice. It is based on 41 semi-structured interviews conducted in the United Kingdom. The sample comprised patients or parents of patients: without a diagnosis; recently offered a test for a condition or carrier risk; with a rare condition; with a variant of unknown significance - some of whom had been recontacted. Participants were recruited both via the National Health Service (NHS) and through online, condition-specific support groups. Most respondents viewed recontacting as desirable, however there were different opinions and expectations about what type of new information should trigger recontacting. An awareness of the potential psychological impact of receiving new information led some to suggest that recontacting should be planned, and tailored to the nature of the new information and the specific situation of patients and families. The lack of clarity about lines of responsibility for recontacting and perceptions of resource constraints in the NHS tended to mitigate respondents' favourable positions towards recontacting and their preferences. Some respondents argued that recontacting could have a preventative value and reduce the cost of healthcare. Others challenged the idea that resources should be used to implement formalised recontacting systems - via arguments that there are 'more pressing' public health priorities, and for the need for healthcare services to offer care to new patients.
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http://dx.doi.org/10.1038/ejhg.2017.122DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5602023PMC
October 2017

Polycystic Kidney Disease with Hyperinsulinemic Hypoglycemia Caused by a Promoter Mutation in Phosphomannomutase 2.

J Am Soc Nephrol 2017 08 3;28(8):2529-2539. Epub 2017 Apr 3.

University College London Centre for Nephrology, University College London, London, United Kingdom.

Hyperinsulinemic hypoglycemia (HI) and congenital polycystic kidney disease (PKD) are rare, genetically heterogeneous disorders. The co-occurrence of these disorders (HIPKD) in 17 children from 11 unrelated families suggested an unrecognized genetic disorder. Whole-genome linkage analysis in five informative families identified a single significant locus on chromosome 16p13.2 (logarithm of odds score 6.5). Sequencing of the coding regions of all linked genes failed to identify biallelic mutations. Instead, we found in all patients a promoter mutation (c.-167G>T) in the phosphomannomutase 2 gene (), either homozygous or with coding mutations. encodes a key enzyme in N-glycosylation. Abnormal glycosylation has been associated with PKD, and we found that deglycosylation in cultured pancreatic cells altered insulin secretion. Recessive coding mutations in cause congenital disorder of glycosylation type 1a (CDG1A), a devastating multisystem disorder with prominent neurologic involvement. Yet our patients did not exhibit the typical clinical or diagnostic features of CDG1A. the promoter mutation associated with decreased transcriptional activity in patient kidney cells and impaired binding of the transcription factor ZNF143. analysis suggested an important role of ZNF143 for the formation of a chromatin loop including We propose that the promoter mutation alters tissue-specific chromatin loop formation, with consequent organ-specific deficiency of PMM2 leading to the restricted phenotype of HIPKD. Our findings extend the spectrum of genetic causes for both HI and PKD and provide insights into gene regulation and pleiotropy.
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http://dx.doi.org/10.1681/ASN.2016121312DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5533241PMC
August 2017

De novo SETD5 nonsense mutation associated with diaphragmatic hernia and severe cerebral cortical dysplasia.

Clin Dysmorphol 2017 Apr;26(2):95-97

Departments of aClinical GeneticsbMolecular Genetics, Royal Devon and Exeter NHS Foundation Trust, ExetercDepartment of Neonatology, Corniche Hospital, Abu Dhabi, United Arab Emirates.

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http://dx.doi.org/10.1097/MCD.0000000000000144DOI Listing
April 2017

Digesting GWAS.

Cell Mol Gastroenterol Hepatol 2016 Sep 28;2(5):542-543. Epub 2016 Jul 28.

University of Exeter Medical School, Clinical Genetics, Royal Devon and Exeter Hospital, Exeter, United Kingdom.

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http://dx.doi.org/10.1016/j.jcmgh.2016.07.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5042883PMC
September 2016

Recontacting in clinical practice: an investigation of the views of healthcare professionals and clinical scientists in the United Kingdom.

Eur J Hum Genet 2017 02 4;25(3):275-279. Epub 2017 Jan 4.

Egenis, University of Exeter, Exeter, UK.

This article explores the views and experiences of healthcare professionals and clinical scientists in genetics about the existence of a duty and/or responsibility to recontact former patients when the genetic information relevant to their health, or that of family members, changes in a potentially important manner. It is based on N=30 semi-structured interviews guided by vignettes of recontacting scenarios. The sample included healthcare professionals in the United Kingdom from different medical specialties (clinical genetics, other 'mainstream' specialties now offering genetic testing), and scientists from regional genetics laboratories. While viewing recontacting as desirable under certain circumstances, most respondents expressed concerns about its feasibility within the current constraints of the National Health Service (NHS). The main barriers identified were insufficient resources (time, staff, and suitable IT infrastructures) and lack of clarity about role boundaries and responsibilities. All of these are further complicated by genetic testing being increasingly offered by mainstream specialties. Reaching a consensus about roles and responsibilities of clinical specialties with regard to recontacting former patients in the light of evolving genetic information, and about what resources and infrastructures would be needed, was generally seen as a pre-requisite to developing guidelines about recontact.
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http://dx.doi.org/10.1038/ejhg.2016.188DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5315519PMC
February 2017

Recontact in clinical practice: a survey of clinical genetics services in the United Kingdom.

Genet Med 2016 09 18;18(9):876-81. Epub 2016 Feb 18.

Egenis, University of Exeter, Exeter, UK.

Purpose: To ascertain whether and how recontacting occurs in the United Kingdom.

Method: A Web-based survey was administered online between October 2014 and July 2015. A link to the survey was circulated via an e-mail invitation to the clinical leads of the United Kingdom's 23 clinical genetics services, with follow-up with senior clinical genetics staff.

Results: The majority of UK services reported that they recontact patients and their family members. However, recontacting generally occurs in an ad hoc fashion when an unplanned event causes clinicians to review a file (a "trigger"). There are no standardized recontacting practices in the United Kingdom. More than half of the services were unsure whether formalized recontacting systems should be implemented. Some suggested greater patient involvement in the process of recontacting.

Conclusion: This research suggests that a thorough evaluation of the efficacy and sustainability of potential recontacting systems within the National Health Service would be necessary before deciding whether and how to implement such a service or to create guidelines on best-practice models.Genet Med 18 9, 876-881.
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http://dx.doi.org/10.1038/gim.2015.194DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5052431PMC
September 2016

Total anomalous pulmonary venous drainage in a patient with Koolen syndrome (del17q21.31).

Clin Dysmorphol 2015 Jul;24(3):132-4

aPeninsula Clinical Genetics Service, Royal Devon and Exeter NHS Foundation Trust, Exeter bPaediatric Cardiology Department, Oxford University Hospitals NHS Trust, Oxford, UK.

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http://dx.doi.org/10.1097/MCD.0000000000000082DOI Listing
July 2015

Whole exome sequencing in family trios reveals de novo mutations in PURA as a cause of severe neurodevelopmental delay and learning disability.

J Med Genet 2014 Dec 23;51(12):806-13. Epub 2014 Oct 23.

Wessex Clinical Genetics Service, Princess Anne Hospital, Southampton, UK Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, Hampshire, UK.

Background: De novo mutations are emerging as an important cause of neurocognitive impairment, and whole exome sequencing of case-parent trios is a powerful way of detecting them. Here, we report the findings in four such trios.

Methods: The Deciphering Developmental Disorders study is using whole exome sequencing in family trios to investigate children with severe, sporadic, undiagnosed developmental delay. Three of our patients were ascertained from the first 1133 children to have been investigated through this large-scale study. Case 4 was a phenotypically isolated case recruited into an undiagnosed rare disorders sequencing study.

Results: Protein-altering de novo mutations in PURA were identified in four subjects. They include two different frameshifts, one inframe deletion and one missense mutation. PURA encodes Pur-α, a highly conserved multifunctional protein that has an important role in normal postnatal brain development in animal models. The associated human phenotype of de novo heterozygous mutations in this gene is variable, but moderate to severe neurodevelopmental delay and learning disability are common to all. Neonatal hypotonia, early feeding difficulties and seizures, or 'seizure-like' movements, were also common. Additionally, it is suspected that anterior pituitary dysregulation may be within the spectrum of this disorder. Psychomotor developmental outcomes appear variable between patients, and we propose a possible genotype-phenotype correlation, with disruption of Pur repeat III resulting in a more severe phenotype.

Conclusions: These findings provide definitive evidence for the role of PURA in causing a variable syndrome of neurodevelopmental delay, learning disability, neonatal hypotonia, feeding difficulties, abnormal movements and epilepsy in humans, and help clarify the role of PURA in the previously described 5q31.3 microdeletion phenotype.
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http://dx.doi.org/10.1136/jmedgenet-2014-102798DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4251168PMC
December 2014

Factors determining penetrance in familial atypical haemolytic uraemic syndrome.

J Med Genet 2014 Nov 26;51(11):756-64. Epub 2014 Sep 26.

Peninsula Clinical Genetics Service, Royal Devon & Exeter NHS Foundation Trust, Royal Devon & Exeter Hospital (Heavitree), Exeter, UK University of Exeter Medical School, University of Exeter, Exeter, UK.

Background: Inherited abnormalities of complement are found in ∼60% of patients with atypical haemolytic uraemic syndrome (aHUS). Such abnormalities are not fully penetrant. In this study, we have estimated the penetrance of the disease in three families with a CFH mutation (c.3643C>G; p. Arg1215Gly) in whom a common lineage is probable. 25 individuals have been affected with aHUS with three peaks of incidence-early childhood (n=6), early adulthood (n=11) and late adulthood (n=8). Eighteen individuals who have not developed aHUS carry the mutation.

Methods: We estimated penetrance at the ages of 4, 27, 60 and 70 years as both a binary and a survival trait using MLINK and Mendel. We genotyped susceptibility factors in CFH, CD46 and CFHR1 in affected and unaffected carriers.

Results And Conclusions: We found that the estimates of penetrance at the age of 4 years ranged from <0.01 to 0.10, at the age of 27 years from 0.16 to 0.29, at the age of 60 years from 0.39 to 0.51 and at the age of 70 years from 0.44 to 0.64. We found that the CFH haplotype on the allele not carrying the CFH mutation had a significant effect on disease penetrance. In this family, we did not find that the CD46 haplotypes had a significant effect on penetrance.
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http://dx.doi.org/10.1136/jmedgenet-2014-102498DOI Listing
November 2014

Next generation sequencing of chromosomal rearrangements in patients with split-hand/split-foot malformation provides evidence for DYNC1I1 exonic enhancers of DLX5/6 expression in humans.

J Med Genet 2014 Apr 23;51(4):264-7. Epub 2014 Jan 23.

Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK.

Objective: Split-hand/foot malformation type 1 is an autosomal dominant condition with reduced penetrance and variable expression. We report three individuals from two families with split-hand/split-foot malformation (SHFM) in whom next generation sequencing was performed to investigate the cause of their phenotype.

Methods And Results: The first proband has a de novo balanced translocation t(2;7)(p25.1;q22) identified by karyotyping. Whole genome sequencing showed that the chromosome 7 breakpoint is situated within the SHFM1 locus on chromosome 7q21.3. This separates the DYNC1I1 exons recently identified as limb enhancers in mouse studies from their target genes, DLX5 and DLX6. In the second family, X-linked recessive inheritance was suspected and exome sequencing was performed to search for a mutation in the affected proband and his uncle. No coding mutation was found within the SHFM2 locus at Xq26 or elsewhere in the exome, but a 106 kb deletion within the SHFM1 locus was detected through copy number analysis. Genome sequencing of the deletion breakpoints showed that the DLX5 and DLX6 genes are disomic but the putative DYNC1I1 exon 15 and 17 enhancers are deleted.

Conclusions: Exome sequencing identified a 106 kb deletion that narrows the SHFM1 critical region from 0.9 to 0.1 Mb and confirms a key role of DYNC1I1 exonic enhancers in normal limb formation in humans.
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http://dx.doi.org/10.1136/jmedgenet-2013-102142DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3963551PMC
April 2014

From the Ottomans to the present day: 150 years of Scottish medical charity in the Holy Land.

BMJ 2013 Dec 12;347:f6994. Epub 2013 Dec 12.

Royal Devon and Exeter Hospital, Exeter EX1 2ED, UK.

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http://dx.doi.org/10.1136/bmj.f6994DOI Listing
December 2013

Mutation of HES7 in a large extended family with spondylocostal dysostosis and dextrocardia with situs inversus.

Am J Med Genet A 2013 Sep 29;161A(9):2244-9. Epub 2013 Jul 29.

Developmental and Stem Cell Biology Division, Victor Chang Cardiac Research Institute, Sydney, Australia.

Spondylocostal dysotosis (SCD) is a rare developmental congenital abnormality of the axial skeleton. Mutation of genes in the Notch signaling pathway cause SCD types 1-5. Dextrocardia with situs inversus is a rare congenital malformation in which the thoracic and abdominal organs are mirror images of normal. Such laterality defects are associated with gene mutations in the Nodal signaling pathway or cilia assembly or function. We investigated two distantly related individuals with a rare combination of severe segmental defects of the vertebrae (SDV) and dextrocardia with situs inversus. We found that both individuals were homozygous for the same mutation in HES7, and that this mutation caused a significant reduction of HES7 protein function; HES7 mutation causes SCD4. Two other individuals with SDV from two unrelated families were found to be homozygous for the same mutation. Interestingly, although the penetrance of the vertebral defects was complete, only 3/7 had dextrocardia with situs inversus, suggesting randomization of left-right patterning. Two of the affected individuals presented with neural tube malformations including myelomeningocele, spina bifida occulta and/or Chiari II malformation. Such neural tube phenotypes are shared with the originally identified SCD4 patient, but have not been reported in the other forms of SCD. In conclusion, it appears that mutation of HES7 is uniquely associated with defects in vertebral, heart and neural tube formation, and this observation will help provide a discriminatory diagnostic guide in patients with SCD, as well as inform molecular genetic testing.
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http://dx.doi.org/10.1002/ajmg.a.36073DOI Listing
September 2013