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AIMSWERNER SYNDROME IS A RARE PREMATURE AGEING AUTOSOMAL RECESSIVE DISORDER CAUSED BY PATHOGENIC VARIANTS IN THE WRN GENE. PEOPLE WITH WERNER SYNDROME MAY DEVELOP DIABETES MELLITUS. CHRONIC FOOT ULCERATION IS SEEN, WITH SOME CHARACTERISTICS OVERLAPPING WITH DIABETIC FOOT DISEASE. HOWEVER, THE CLINICAL COURSE OF THE ULCERATION IS ATYPICAL OF DIABETIC FOOT DISEASE. WE PRESENT FOUR SIBLINGS FROM AN IRISH TRAVELLER FAMILY WITH WERNER SYNDROME TO HIGHLIGHT THE COMPLEXITY OF THIS CONDITION. THE IRISH TRAVELLER POPULATION ARE AN INDIGENOUS, ENDOGAMOUS POPULATION IN WHICH CONSANGUINITY IS COMMON. AS A RESULT, RARE AUTOSOMAL RECESSIVE DISORDERS ARE PREVALENT AMONG THIS POPULATION: . METHODS: We describe our experience managing the complex foot disease seen in all four siblings. Foot complications present in the siblings include painful peripheral neuropathy, chronic foor ulceration, underlying osteomyelitis and acral melanoma. RESULTS: The cases are described individually, with a particular focus on the complex foot disease associated with the condition. CONCLUSIONS: Although the siblings attend a diabetic foot clinic, we suggest that the combination of clinical features seen in these cases is unique to Werner syndrome and warrants the title 'Werner Syndrome' (rather than 'Diabetic') foot.
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Pie Diabético , Hermanos , Síndrome de Werner , Humanos , Síndrome de Werner/genética , Síndrome de Werner/complicaciones , Síndrome de Werner/diagnóstico , Masculino , Femenino , Persona de Mediana Edad , Adulto , Pie Diabético/diagnóstico , Irlanda , Melanoma/genética , Melanoma/diagnóstico , Melanoma/complicaciones , Osteomielitis/diagnóstico , Osteomielitis/genética , Osteomielitis/complicaciones , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/genética , Consanguinidad , Úlcera del Pie/genética , Úlcera del Pie/etiologíaRESUMEN
The International Rare Diseases Research Consortium (IRDiRC) Diagnostic Scientific Committee (DSC) is charged with discussion and contribution to progress on diagnostic aspects of the IRDiRC core mission. Specifically, IRDiRC goals include timely diagnosis, use of globally coordinated diagnostic pipelines, and assessing the impact of rare diseases on affected individuals. As part of this mission, the DSC endeavored to create a list of research priorities to achieve these goals. We present a discussion of those priorities along with aspects of current, global rare disease needs and opportunities that support our prioritization. In support of this discussion, we also provide clinical vignettes illustrating real-world examples of diagnostic challenges.
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Enfermedades Raras , Enfermedades Raras/diagnóstico , Enfermedades Raras/genética , Humanos , Salud Global/normasRESUMEN
BACKGROUND: Inherited cardiomyopathies (HCM, DCM, ACM) and cardiac ion channelopathies (long QT/Brugada syndromes, CPVT) are associated with significant morbidity and mortality; however, diagnosis of a familial pathogenic variant in a proband allows for subsequent cascade screening of their at-risk relatives. AIMS: We investigated the diagnostic yield from cardiac gene panel testing and reviewed variants of uncertain significance from patients attending three specialist cardiogenetics services in Ireland in the years 2002 to 2020. RESULTS: Reviewing molecular genetic diagnostic reports of 834 patients from 820 families, the initial diagnostic yield of pathogenic/likely pathogenic variants was 237/834 patients (28.4%), increasing to 276/834 patients (33.1%) following re-evaluation of cases with variant(s) of uncertain significance. Altogether, 42/85 patients with VUS reviewed (49.4%) had a re-classification that could change their clinical management. Females were more likely to carry pathogenic/likely pathogenic variants than males (139/374, 37.2% vs 137/460, 29.8%, respectively, p = 0.03), and the diagnostic yields were highest in the 0 to < 2 years age group (6/12, 50.0%) and amongst those tested for cardiomyopathy gene panels (13/35, 37.1%). Variants in the MYBPC3/MYH7 (87/109, 79.8%) and KCNQ1/KCNH2 (91/100, 91.0%) genes were the predominant genetic causes for hypertrophic cardiomyopathy and long QT syndrome, respectively. CONCLUSION: Our study highlights the importance of collation and review of pre-ACMG genetic variants to increase diagnostic utility of genetic testing for inherited heart disease. Almost half of patients with pre-ACMG VUS reviewed had their variant re-classified to likely pathogenic/likely benign which resulted in a positive clinical impact for patients and their families.
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Pruebas Genéticas , Humanos , Femenino , Masculino , Pruebas Genéticas/métodos , Pruebas Genéticas/estadística & datos numéricos , Adulto , Adolescente , Niño , Lactante , Preescolar , Persona de Mediana Edad , Irlanda , Adulto Joven , Recién Nacido , Miosinas Cardíacas/genética , Anciano , Cardiomiopatías/genética , Cardiomiopatías/diagnósticoRESUMEN
Translation elongation factor eEF1A2 constitutes the alpha subunit of the elongation factor-1 complex, responsible for the enzymatic binding of aminoacyl-tRNA to the ribosome. Since 2012, 21 pathogenic missense variants affecting EEF1A2 have been described in 42 individuals with a severe neurodevelopmental phenotype including epileptic encephalopathy and moderate to profound intellectual disability (ID), with neurological regression in some patients. Through international collaborative call, we collected 26 patients with EEF1A2 variants and compared them to the literature. Our cohort shows a significantly milder phenotype. 83% of the patients are walking (vs. 29% in the literature), and 84% of the patients have language skills (vs. 15%). Three of our patients do not have ID. Epilepsy is present in 63% (vs. 93%). Neurological examination shows a less severe phenotype with significantly less hypotonia (58% vs. 96%), and pyramidal signs (24% vs. 68%). Cognitive regression was noted in 4% (vs. 56% in the literature). Among individuals over 10 years, 56% disclosed neurocognitive regression, with a mean age of onset at 2 years. We describe 8 novel missense variants of EEF1A2. Modeling of the different amino-acid sites shows that the variants associated with a severe phenotype, and the majority of those associated with a moderate phenotype, cluster within the switch II region of the protein and thus may affect GTP exchange. In contrast, variants associated with milder phenotypes may impact secondary functions such as actin binding. We report the largest cohort of individuals with EEF1A2 variants thus far, allowing us to expand the phenotype spectrum and reveal genotype-phenotype correlations.
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BACKGROUND: The ITPR1 gene encodes the inositol 1,4,5-trisphosphate (IP3 ) receptor type 1 (IP3 R1), a critical player in cerebellar intracellular calcium signaling. Pathogenic missense variants in ITPR1 cause congenital spinocerebellar ataxia type 29 (SCA29), Gillespie syndrome (GLSP), and severe pontine/cerebellar hypoplasia. The pathophysiological basis of the different phenotypes is poorly understood. OBJECTIVES: We aimed to identify novel SCA29 and GLSP cases to define core phenotypes, describe the spectrum of missense variation across ITPR1, standardize the ITPR1 variant nomenclature, and investigate disease progression in relation to cerebellar atrophy. METHODS: Cases were identified using next-generation sequencing through the Deciphering Developmental Disorders study, the 100,000 Genomes project, and clinical collaborations. ITPR1 alternative splicing in the human cerebellum was investigated by quantitative polymerase chain reaction. RESULTS: We report the largest, multinational case series of 46 patients with 28 unique ITPR1 missense variants. Variants clustered in functional domains of the protein, especially in the N-terminal IP3 -binding domain, the carbonic anhydrase 8 (CA8)-binding region, and the C-terminal transmembrane channel domain. Variants outside these domains were of questionable clinical significance. Standardized transcript annotation, based on our ITPR1 transcript expression data, greatly facilitated analysis. Genotype-phenotype associations were highly variable. Importantly, while cerebellar atrophy was common, cerebellar volume loss did not correlate with symptom progression. CONCLUSIONS: This dataset represents the largest cohort of patients with ITPR1 missense variants, expanding the clinical spectrum of SCA29 and GLSP. Standardized transcript annotation is essential for future reporting. Our findings will aid in diagnostic interpretation in the clinic and guide selection of variants for preclinical studies. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Aniridia , Anhidrasas Carbónicas , Ataxia Cerebelosa , Discapacidad Intelectual , Trastornos del Movimiento , Degeneraciones Espinocerebelosas , Humanos , Ataxia Cerebelosa/genética , Mutación Missense/genética , Trastornos del Movimiento/complicaciones , Atrofia , Receptores de Inositol 1,4,5-Trifosfato/química , Receptores de Inositol 1,4,5-Trifosfato/genética , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Anhidrasas Carbónicas/genética , Anhidrasas Carbónicas/metabolismo , Péptidos y Proteínas de Señalización Intracelular/genéticaRESUMEN
AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) receptors (AMPARs) mediate fast excitatory neurotransmission in the brain. AMPARs form by homo- or heteromeric assembly of subunits encoded by the GRIA1-GRIA4 genes, of which only GRIA3 is X-chromosomal. Increasing numbers of GRIA3 missense variants are reported in patients with neurodevelopmental disorders (NDD), but only a few have been examined functionally. Here, we evaluated the impact on AMPAR function of one frameshift and 43 rare missense GRIA3 variants identified in patients with NDD by electrophysiological assays. Thirty-one variants alter receptor function and show loss-of-function (LoF) or gain-of-function (GoF) properties, whereas 13 appeared neutral. We collected detailed clinical data from 25 patients (from 23 families) harbouring 17 of these variants. All patients had global developmental impairment, mostly moderate (9/25) or severe (12/25). Twelve patients had seizures, including focal motor (6/12), unknown onset motor (4/12), focal impaired awareness (1/12), (atypical) absence (2/12), myoclonic (5/12), and generalized tonic-clonic (1/12) or atonic (1/12) seizures. The epilepsy syndrome was classified as developmental and epileptic encephalopathy in eight patients, developmental encephalopathy without seizures in 13 patients, and intellectual disability with epilepsy in four patients. Limb muscular hypotonia was reported in 13/25, and hypertonia in 10/25. Movement disorders were reported in 14/25, with hyperekplexia or non-epileptic erratic myoclonus being the most prevalent feature (8/25). Correlating receptor functional phenotype with clinical features revealed clinical features for GRIA3-associated NDDs and distinct NDD phenotypes for LoF and GoF variants. GoF variants were associated with more severe outcomes: patients were younger at the time of seizure onset (median age one month), hypertonic, and more often had movement disorders, including hyperekplexia. Patients with LoF variants were older at the time of seizure onset (median age 16 months), hypotonic, and had sleeping disturbances. LoF and GoF variants were disease-causing in both sexes but affected males often carried de novo or hemizygous LoF variants inherited from healthy mothers, whereas all but one affected females had de novo heterozygous GoF variants.
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Type I interferon (IFN) signalling is tightly controlled. Upon recognition of DNA by cyclic GMP-AMP synthase (cGAS), stimulator of interferon genes (STING) translocates along the endoplasmic reticulum (ER)-Golgi axis to induce IFN signalling. Termination is achieved through autophagic degradation or recycling of STING by retrograde Golgi-to-ER transport. Here, we identify the GTPase ADP-ribosylation factor 1 (ARF1) as a crucial negative regulator of cGAS-STING signalling. Heterozygous ARF1 missense mutations cause a previously unrecognized type I interferonopathy associated with enhanced IFN-stimulated gene expression. Disease-associated, GTPase-defective ARF1 increases cGAS-STING dependent type I IFN signalling in cell lines and primary patient cells. Mechanistically, mutated ARF1 perturbs mitochondrial morphology, causing cGAS activation by aberrant mitochondrial DNA release, and leads to accumulation of active STING at the Golgi/ERGIC due to defective retrograde transport. Our data show an unexpected dual role of ARF1 in maintaining cGAS-STING homeostasis, through promotion of mitochondrial integrity and STING recycling.
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Interferón Tipo I , Humanos , Factor 1 de Ribosilacion-ADP/genética , Factor 1 de Ribosilacion-ADP/metabolismo , Interferón Tipo I/metabolismo , Proteínas de la Membrana/metabolismo , Nucleotidiltransferasas/genética , Nucleotidiltransferasas/metabolismo , Transducción de SeñalRESUMEN
PURPOSE: ATP2B2 encodes the variant-constrained plasma-membrane calcium-transporting ATPase-2, expressed in sensory ear cells and specialized neurons. ATP2B2/Atp2b2 variants were previously linked to isolated hearing loss in patients and neurodevelopmental deficits with ataxia in mice. We aimed to establish the association between ATP2B2 and human neurological disorders. METHODS: Multinational case recruitment, scrutiny of trio-based genomics data, in silico analyses, and functional variant characterization were performed. RESULTS: We assembled 7 individuals harboring rare, predicted deleterious heterozygous ATP2B2 variants. The alleles comprised 5 missense substitutions that affected evolutionarily conserved sites and 2 frameshift variants in the penultimate exon. For 6 variants, a de novo status was confirmed. Unlike described patients with hearing loss, the individuals displayed a spectrum of neurological abnormalities, ranging from ataxia with dystonic features to complex neurodevelopmental manifestations with intellectual disability, autism, and seizures. Two cases with recurrent amino-acid variation showed distinctive overlap with cerebellar atrophy-associated ataxia and epilepsy. In cell-based studies, all variants caused significant alterations in cytosolic calcium handling with both loss- and gain-of-function effects. CONCLUSION: Presentations in our series recapitulate key phenotypic aspects of Atp2b2-mouse models and underline the importance of precise calcium regulation for neurodevelopment and cerebellar function. Our study documents a role for ATP2B2 variants in causing heterogeneous neurodevelopmental and movement-disorder syndromes.
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Ataxia Cerebelosa , Distonía , Pérdida Auditiva , Discapacidad Intelectual , Trastornos del Neurodesarrollo , Animales , Humanos , Ratones , Síntomas Conductuales , Calcio , Ataxia Cerebelosa/genética , Distonía/genética , Discapacidad Intelectual/genética , Trastornos del Neurodesarrollo/genética , Fenotipo , ATPasas Transportadoras de Calcio de la Membrana Plasmática , Convulsiones/genéticaRESUMEN
We present a female patient with a complex sex chromosomal rearrangement [GRCh38] Xp22.33(10701_981101)x1,Yq11.221q11.23(13948013_26483746)x1 who conceived spontaneously and carried a healthy pregnancy to term. The patient presented with extreme short stature (more than 4SD below expected) and a bilateral Madelung deformity suggesting a possible SHOX deletion. The patient was otherwise medically well. This patient's short stature was found to be a result of a complex chromosome rearrangement involving a partial X chromosome deletion, which included the SHOX gene and a gain of Y chromosomal material. The Y chromosome material did not contain the SRY gene locus. This is the first recorded case to date of this rearrangement in a female who spontaneously conceived which resulted in a live birth. This patient had normal external and internal anatomy and normal endocrine evaluation with normal puberty. X-inactivation studies revealed no evidence of skewed inactivation.
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Enanismo , Proteínas de Homeodominio , Embarazo , Humanos , Femenino , Proteínas de Homeodominio/genética , Proteína de la Caja Homeótica de Baja Estatura/genética , Cromosoma Y , Aberraciones Cromosómicas , Trastornos del Crecimiento/genéticaRESUMEN
Triplication of chromosomal region 1p36.3 is a rare genomic rearrangement. In this report, we delineate the phenotypic spectrum associated with 1p36.3 triplications. We describe four patients with microtriplications of variable size, but with a strong phenotypic overlap, and compare them to previously described patients with an isolated triplication or duplication of this region. The 1p36.3 triplication syndrome is associated with a distinct phenotype, characterized by global developmental delay, moderate intellectual disability, seizures, behavioral problems, and specific facial dysmorphic features, including ptosis, hypertelorism, and arched eyebrows. The de novo occurrence of these microtriplications demonstrates the reduced reproductive fitness associated with this genotype, in contrast to 1p36.3 duplications which are mostly inherited and can be associated with similar facial features but with a less severe developmental phenotype. The shared triplicated region encompasses four disease-related genes of which GABRD and SKI are most likely to contribute to the phenotype.
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Discapacidades del Desarrollo , Discapacidad Intelectual , Niño , Humanos , Cromosomas Humanos Par 3 , Discapacidades del Desarrollo/genética , Cara , Discapacidad Intelectual/genética , Fenotipo , Receptores de GABA-A/genética , SíndromeRESUMEN
BACKGROUND: Clinical genetics is an under-resourced service in the Republic of Ireland. There can be a number of avenues that lead to barriers in patient triage noted within the department. AIMS: To evaluate the reasons for referral rejection in the triage pathway. To identify the time and cost implications. METHODS: A retrospective analysis of rejected referrals consecutively triaged by one consultant was undertaken over an 18-month period. Calculation of costs used data from a previous study. RESULTS: The consultant rejected 128/1581 (8.3%) of referrals. The rejection reasons included the following: 75% had not included the family/patient genetic report, 10% were conditions not accepted by our service, 8% redirected to other specialities, 3% given written advice in lieu of appointment and 4% for other reasons. Follow-up information was requested on 78% of rejected referrals. For 57% this was received; in 43% no response was received, and these cases remain closed. Median response time was 33 days. Of those who sent back appropriate information, 39% remain on waiting list, 50% attended OPD or were given appropriate advice, 5% did not attend and 4% had alternative follow-up pathways. The estimated time cost of rejected referrals equated to 88.5 h (59 h/year). Using this as our cost of rejection letter, it equated 11,878.4/year departmental cost. CONCLUSION: The majority of referrals are rejected for non-enclosure of patient genetic reports. Many referrals would have accepted to the waiting list if the appropriate report had been attached. This means patients at risk of genetic disorders are not accessing clinical services because the referrer is not providing the necessary information to allow triage. Active management of the waiting list via upfront letters is costly, with a 57% response rate. Should similar rejection rates exist in other specialities, we estimate this would equate to a cost of 2,714,214.40/year to the HSE.
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Atención a la Salud , Triaje , Humanos , Irlanda , Estudios Retrospectivos , Derivación y ConsultaRESUMEN
De novo truncating and splicing pathogenic variants in the Additional Sex Combs-Like 3 (ASXL3) gene are known to cause neurodevelopmental delay, intellectual disability, behavioral difficulties, hypotonia, feeding problems and characteristic facial features. We previously reported 45 patients with ASXL3-related disorder including three individuals with a familial variant. Here we report the detailed clinical and molecular characteristics of these three families with inherited ASXL3-related disorder. First, a father and son with c.2791_2792del p.Gln931fs pathogenic variant. The second, a mother, daughter and son with c.4534C > T, p.Gln1512Ter pathogenic variant. The third, a mother and her daughter with c.4441dup, p.Leu1481fs maternally inherited pathogenic variant. This report demonstrates intrafamilial phenotypic heterogeneity and confirms heritability of ASXL3-related disorder.
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Anomalías Múltiples , Discapacidades del Desarrollo , Discapacidad Intelectual , Niño , Femenino , Humanos , Discapacidades del Desarrollo/genética , Discapacidad Intelectual/diagnóstico , Discapacidad Intelectual/genética , Fenotipo , Síndrome , Factores de Transcripción/genéticaRESUMEN
PURPOSE: Biallelic PIGN variants have been described in Fryns syndrome, multiple congenital anomalies-hypotonia-seizure syndrome (MCAHS), and neurologic phenotypes. The full spectrum of clinical manifestations in relation to the genotypes is yet to be reported. METHODS: Genotype and phenotype data were collated and analyzed for 61 biallelic PIGN cases: 21 new and 40 previously published cases. Functional analysis was performed for 2 recurrent variants (c.2679C>G p.Ser893Arg and c.932T>G p.Leu311Trp). RESULTS: Biallelic-truncating variants were detected in 16 patients-10 with Fryns syndrome, 1 with MCAHS1, 2 with Fryns syndrome/MCAHS1, and 3 with neurologic phenotype. There was an increased risk of prenatal or neonatal death within this group (6 deaths were in utero or within 2 months of life; 6 pregnancies were terminated). Incidence of polyhydramnios, congenital anomalies (eg, diaphragmatic hernia), and dysmorphism was significantly increased. Biallelic missense or mixed genotype were reported in the remaining 45 cases-32 showed a neurologic phenotype and 12 had MCAHS1. No cases of diaphragmatic hernia or abdominal wall defects were seen in this group except patient 1 in which we found the missense variant p.Ser893Arg to result in functionally null alleles, suggesting the possibility of an undescribed functionally important region in the final exon. For all genotypes, there was complete penetrance for developmental delay and near-complete penetrance for seizures and hypotonia in patients surviving the neonatal period. CONCLUSION: We have expanded the described spectrum of phenotypes and natural history associated with biallelic PIGN variants. Our study shows that biallelic-truncating variants usually result in the more severe Fryns syndrome phenotype, but neurologic problems, such as developmental delay, seizures, and hypotonia, present across all genotypes. Functional analysis should be considered when the genotypes do not correlate with the predicted phenotype because there may be other functionally important regions in PIGN that are yet to be discovered.
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Anomalías Múltiples , Trastornos Congénitos de Glicosilación , Epilepsia , Hernia Diafragmática , Embarazo , Femenino , Humanos , Hipotonía Muscular/genética , Epilepsia/genética , Anomalías Múltiples/genética , Hernia Diafragmática/genética , Convulsiones/genética , Fenotipo , Estudios de Asociación Genética , SíndromeRESUMEN
PURPOSE: ZMYND8 encodes a multidomain protein that serves as a central interactive hub for coordinating critical roles in transcription regulation, chromatin remodeling, regulation of super-enhancers, DNA damage response and tumor suppression. We delineate a novel neurocognitive disorder caused by variants in the ZMYND8 gene. METHODS: An international collaboration, exome sequencing, molecular modeling, yeast two-hybrid assays, analysis of available transcriptomic data and a knockdown Drosophila model were used to characterize the ZMYND8 variants. RESULTS: ZMYND8 variants were identified in 11 unrelated individuals; 10 occurred de novo and one suspected de novo; 2 were truncating, 9 were missense, of which one was recurrent. The disorder is characterized by intellectual disability with variable cardiovascular, ophthalmologic and minor skeletal anomalies. Missense variants in the PWWP domain of ZMYND8 abolish the interaction with Drebrin and missense variants in the MYND domain disrupt the interaction with GATAD2A. ZMYND8 is broadly expressed across cell types in all brain regions and shows highest expression in the early stages of brain development. Neuronal knockdown of the DrosophilaZMYND8 ortholog results in decreased habituation learning, consistent with a role in cognitive function. CONCLUSION: We present genomic and functional evidence for disruption of ZMYND8 as a novel etiology of syndromic intellectual disability.