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    X-linked intellectual developmental disorder with onset of neonatal heart failure: A case report and literature review
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    Abstract:
    X-linked intellectual developmental disorder is a rare X-linked genetic disease, manifested as heart disease, intellectual impairment, and developmental disorders. We report a male infant who presented with dyspnea after birth. Physical examination on admission revealed poor responsiveness, deep eye sockets, a small mandible, abnormalities of the outer ears, and reduced limb muscle tone. The child was moaning with shortness of breath and a positive three-concave sign without pulmonary rales. The heart sounds were weak with a grade 2/6 diastolic heart murmur. Echocardiography showed an enlarged heart with increased trabeculae in the left ventricular muscle wall. X-linked mental retardation syndrome type 34(MRXS34, OMIM# 300967) was diagnosed after exome sequencing showed a c.1131G > A hemizygous variant in the NONO gene. After timely therapy including respiratory support, cardiac glycosides, and diuresis, the child's condition improved and he was discharged at one month of age. A literature review showed that, to date, 22 live births with X-linked mental retardation have been reported. The NONO-related phenotype can be summarized as a neurological and cardiac developmental disorder, which may be accompanied by multisystem malformations. The present case enriches the knowledge of X-linked intellectual developmental syndromes.
    Intellectual disability (ID) represents a neurodevelopmental disorder, which is characterized by marked defects in the intellectual function and adaptive behavior, with an onset during the developmental period. ID is mainly caused by genetic factors, and it is extremely genetically heterogeneous. This study aims to identify the genetic cause of ID using trio-WES analysis.We recruited four pediatric patients with unexplained ID from non-consanguineous families, who presented at the Department of Pediatrics, Guizhou Provincial People's Hospital. Whole-exome sequencing (WES) and Sanger sequencing validation were performed in the patients and their unaffected parents. Furthermore, conservative analysis and protein structural and functional prediction were performed on the identified pathogenic variants.We identified five novel de novo mutations from four known ID-causing genes in the four included patients, namely COL4A1 (c.2786T>A, p.V929D and c.2797G>A, p.G933S), TBR1 (c.1639_1640insCCCGCAGTCC, p.Y553Sfs*124), CHD7 (c.7013A>T, p.Q2338L), and TUBA1A (c.1350del, p.E450Dfs*34). These mutations were all predicted to be deleterious and were located at highly conserved domains that might affect the structure and function of these proteins.Our findings contribute to expanding the mutational spectrum of ID-related genes and help to deepen the understanding of the genetic causes and heterogeneity of ID.
    Sanger sequencing
    Exome
    Loss function
    Citations (2)
    This study was undertaken to identify all congenital heart disease in infancy, including deaths before diagnosis, to provide a truer picture of the spectrum of congenital heart disease and to assess the 9treatability9 of those dying before diagnosis. All births, infant deaths, and surviving babies with congenital heart disease in one health region in 1985-90 were identified and were classified as 9complex9, 9significant9, or 9minor9. Of the 1074 infants diagnosed in infancy, 185 died and 56 of these (30%) died undiagnosed. Severe non-cardiac malformations were present in 29 of the 56 while 27 were otherwise normal. Cardiovascular abnormalities in the latter group were complex in 13/27 and significant in 14/27. Identification of undiagnosed cardiovascular anomalies will improve epidemiological evaluation of congenital heart disease and, more importantly, earlier recognition of treatable abnormalities may reduce mortality.
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    What is heart failure? what causes heart failure? the public health problem of heart failure pathophysiology of the heart failure syndrome the symptoms and signs of heart failure investigation of the patient with heart failure treatment of heart failure - diuretics treatment for heart failure - ace inhibitors treatment of heart failure - digoxin management of heart failure - non-pharmacological therapy management of concomitant problems in patients with heart failure patients who do not respond to treatment preventions of heart failure.
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    Exome sequencing has greatly impacted the speed at which new disease genes are identified. In the last year alone, six studies have used exome sequencing to identify new genes involved in intellectual disability, a genetically heterogeneous condition affecting 1-3% of the population. These studies encompass the full gamut of modes of inheritance and phenotypic presentation, including syndromic and non-syndromic conditions, sporadic and familial cases, and dominant and recessive inheritance patterns. Because different disease presentations require different approaches to gene discovery, studies of intellectual disability provide a nearly comprehensive showcase of strategies for exome-driven gene discovery. Despite these successes, the etiology of ~60% of cases of intellectual disability remains unknown. The application of exome sequencing to the clinical diagnosis of intellectual disability in the near future will ultimately reduce the number of idiopathic cases and provide a rich source of sequence variation for the identification of new intellectual disability genes.
    Exome
    Human genetics
    Medical genetics
    Abstract Background Intellectual disability is a prevalent neurodevelopmental disorder, with the majority of affected children exhibiting global developmental delay before the age of 5 years. In recent years, certain children have been found to carry homozygous variations of the EEF1D gene, leading to autosomal recessive intellectual disability. However, the pathogenicity of compound heterozygous variations in this gene remains largely unknown. Methods Trio whole‐exome sequencing and copy number variation sequencing were done for the genetic etiological diagnosis of a 3‐year and 11‐month‐old Chinese boy who presented with brachycephaly, severe to profound global developmental delay, and hypotonia in the lower limbs. Results In this case, compound heterozygous variants of the EEF1D gene were found in the child through trio whole‐exome sequencing; one was a splice variant (NM_032378.6:c.1905+1G>A) inherited from his father, and the other was a nonsense variant (NM_032378.6:c.676C>T) inherited from his mother. The nonsense variant leads to the production of a premature termination (p.Gln226*). These variations have the ability to explain the clinical phenotypes of the child. Conclusions Our study expands the variation spectrum and provides compelling evidence for EEF1D as a candidate gene for autosomal recessive intellectual disability. However, due to the deficient number of reported cases, researchers need to further study EEF1D and supplement the clinical phenotypes and treatment measures.
    Compound heterozygosity
    Nonsense
    Global developmental delay
    Nonsense mutation
    Speech delay
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    Investigating novel genetic variants involved in intellectual disability (ID) development is essential. X-linked intellectual disability (XLID) accounts for over 10% of all cases of ID in males. XLID genes are involved in many cellular pathways and processes. Some of them are not specific to the development and functioning of the neural system. The implementation of exome sequencing simplifies the search for novel variants, especially those less expected. Here, we describe a nonsense variant of the XLID gene, WDR13. The mutation c.757C>T (p.Arg253Ter) was uncovered by X-chromosome exome sequencing in males with a familial form of intellectual disability. Quantitative PCR (qPCR) analysis showed that variant c.757C>T caused a significant decrease in WDR13 expression in the patient's fibroblast. Moreover, it dysregulated other genes linked to intellectual disability, such as FMR1, SYN1, CAMK2A, and THOC2. The obtained results indicate the pathogenic nature of the detected variant and suggest that the WDR13 gene interacts with other genes essential for the functioning of the nervous system, especially the synaptic plasticity process.
    Exome
    Nonsense-Mediated Decay
    Nonsense mutation
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    There is a significant level of genetic heterogeneity underlying the phenotype of nonspecific hypotonia with severe intellectual disability. Exome sequencing has proven to be a powerful tool for identifying the underlying molecular basis of such nonspecific, abnormal neurological phenotypes. Mutations in the TBCK gene have been reported associated with very poor, if any, psychomotor development, poor speech, and inability to walk independently. We describe the long‐term phenotypic evolution of a severe nonspecific neurodevelopmental disorder in two siblings born to an Arab‐Moslem family living in northern Israel. Exome sequencing led to identification of a novel homozygous mutation: c.1854delT in the TBCK gene. Abnormal elevated β‐HCG was found in the maternal serum during the two pregnancies, a finding that has not been reported before. These individuals present with severe intellectual disability, no speech, hypotonia, convulsions, and lack of any independent daily skills. © 2016 Wiley Periodicals, Inc.
    Exome
    Muscle Hypotonia
    Human genetics
    Citations (15)
    The recent advent of exome sequencing has allowed for the identification of pathogenic gene variants responsible for a variety of diseases that were previously clinically diagnosed, with no underlying molecular etiology.Among these conditions, intellectual disability is a prevalent heterogeneous condition, presenting itself in a large spectrum of intensity, in some cases associated with congenital malformations, behavioral and various other intellectual development alterations.Here we report on a 36-year-old male patient, with a mild intellectual disability that remained undiagnosed at the molecular level for all his life.Using Nextera Exome Sequencing, a Chr3:9.517.294A>AC (c.3848_3849insC) SETD5 gene insertion was found.This rare variant was classified as likely pathogenic due to its frameshift nature in the gene, in which loss-of-function mutations have been previously reported to cause intellectual disability, as well as a 3p25.3microdeletion phenotype.It is possible that this variant shows partial activity, due to its gene localization, which would explain the patient's mild phenotype when compared with other reports.
    Etiology
    Exome
    Citations (8)