Loss of Function Mutation

功能缺失突变
  • 文章类型: Case Reports
    SATB1(MIM#602075)是一种相对较新的基因,仅在最近几年才报道与神经发育障碍相关,其特征是可变的面部畸形,全球发育迟缓,糟糕或缺席的演讲,改变的脑电图(EEG),和脑部成像异常。迄今为止,已经描述了44名患者/儿童中的大约30种变体,具有异质性的临床表现。在本研究中,我们描述了一个患有轻度智力障碍的新病人,言语障碍,以及脑电图和神经影像学上的非特异性异常。家庭研究确定了一个新的从头移码变体c.1818delG(第(Gln606Hisfs*101))在SATB1中。为了更好地定义所报告的不同类型的SATB1变体中的基因型-表型关联,我们回顾了患者和文献的临床数据,并比较了表现(癫痫活动,EEG异常和异常的脑成像)是由于错义变异而引起的,而不是由于功能丧失/过早终止变异而引起的。我们的分析表明,后一种变异与较不严重,与由于错义变异导致的更严重的表型相比,非特异性临床特征。这些发现为SATB1相关疾病提供了新的见解。
    SATB1 (MIM #602075) is a relatively new gene reported only in recent years in association with neurodevelopmental disorders characterized by variable facial dysmorphisms, global developmental delay, poor or absent speech, altered electroencephalogram (EEG), and brain abnormalities on imaging. To date about thirty variants in forty-four patients/children have been described, with a heterogeneous spectrum of clinical manifestations. In the present study, we describe a new patient affected by mild intellectual disability, speech disorder, and non-specific abnormalities on EEG and neuroimaging. Family studies identified a new de novo frameshift variant c.1818delG (p.(Gln606Hisfs*101)) in SATB1. To better define genotype-phenotype associations in the different types of reported SATB1 variants, we reviewed clinical data from our patient and from the literature and compared manifestations (epileptic activity, EEG abnormalities and abnormal brain imaging) due to missense variants versus those attributable to loss-of-function/premature termination variants. Our analyses showed that the latter variants are associated with less severe, non-specific clinical features when compared with the more severe phenotypes due to missense variants. These findings provide new insights into SATB1-related disorders.
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  • 文章类型: Case Reports
    背景:肾小管发育不全(RTD)是一种严重的疾病,预后不良,严重影响肾脏的近端小管,同时保持解剖学上正常的总体结构。RTD的遗传起源,涉及ACE中的变体,REN,AGT,和AGTR1基因,影响肾素血管紧张素系统(RAS)内的各种酶或受体。这种情况在产前表现为羊水过少,在产后表现为持续性无尿,严重难治性低血压,和颅骨骨化的缺陷。
    方法:在本报告中,我们描述了一个女性患者的案例,尽管接受了多种血管加压药治疗,经历持续性低血压,最终导致5日龄的早逝。虽然有父母血缘关系的历史,无肾脏疾病家族史.来自父母的血液样品和患者的剩余DNA样品进行全基因组测序(WGS)。遗传分析揭示了血管紧张素II受体1型(AGTR1)基因中罕见的纯合功能缺失变异(NM_000685.5;c.415C>T;p.Arg139*)。
    结论:这个案例突出了AGTR1基因功能缺失变异导致RTD的后果,其特点是出生时或新生儿期死亡率高。此外,我们提供了先前报道的AGTR1基因变异的全面综述,这是RTD最少遇到的遗传原因,以及它们相关的临床特征。
    BACKGROUND: Renal tubular dysgenesis (RTD) is a severe disorder with poor prognosis significantly impacting the proximal tubules of the kidney while maintaining an anatomically normal gross structure. The genetic origin of RTD, involving variants in the ACE, REN, AGT, and AGTR1 genes, affects various enzymes or receptors within the Renin angiotensin system (RAS). This condition manifests prenatally with oligohydramninos and postnatally with persistent anuria, severe refractory hypotension, and defects in skull ossification.
    METHODS: In this report, we describe a case of a female patient who, despite receiving multi vasopressor treatment, experienced persistent hypotension, ultimately resulting in early death at five days of age. While there was a history of parental consanguinity, no reported family history of renal disease existed. Blood samples from the parents and the remaining DNA sample of the patient underwent Whole Genome Sequencing (WGS). The genetic analysis revealed a rare homozygous loss of function variant (NM_000685.5; c.415C > T; p.Arg139*) in the Angiotensin II Receptor Type 1 (AGTR1) gene.
    CONCLUSIONS: This case highlights the consequence of loss-of-function variants in AGTR1 gene leading to RTD, which is characterized by high mortality rate at birth or during the neonatal period. Furthermore, we provide a comprehensive review of previously reported variants in the AGTR1 gene, which is the least encountered genetic cause of RTD, along with their associated clinical features.
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  • 文章类型: Review
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  • 文章类型: Systematic Review
    CTNNB1综合征是一种罕见的与发育迟缓相关的神经发育障碍,智力残疾,和延迟或缺席演讲。本研究的目的是系统回顾有关临床表现患病率的可用数据,并评估已发表的CTNNB1综合征患者的表型和基因型之间的相关性。通过对四个主要数据库的系统搜索来确定研究。收集了患者基因突变的信息,产前和新生儿问题,头围,肌肉张力,脑电图和MRI结果,变形特征,眼睛异常,早期发展,语言和理解,行为特征,和其他临床问题。此外,根据症状的严重程度将突变分为5组.该研究显示了CTNNB1综合征患者的广泛基因型和表型变异性。最常见的中重度表型表现为面部畸形,小头畸形,各种运动障碍,语言和认知障碍,和行为异常(例如,自闭症样或攻击性行为)。外显子14和15中发生的无义和错义突变被归类为正常临床结果类别/组,因为它们在其他方面表现出正常表型,除了眼睛异常.还观察到较温和的表型,在外显子13中具有错义和无义突变。常染色体显性遗传CTNNB1综合征包括广泛的临床特征,从正常到严重。虽然突变不能更普遍地按位置分类,通常观察到C末端蛋白区(外显子13、14、15)与较温和的表型相关。
    The CTNNB1 Syndrome is a rare neurodevelopmental disorder associated with developmental delay, intellectual disability, and delayed or absent speech. The aim of the present study is to systematically review the available data on the prevalence of clinical manifestations and to evaluate the correlation between phenotype and genotype in published cases of patients with CTNNB1 Syndrome. Studies were identified by systematic searches of four major databases. Information was collected on patients\' genetic mutations, prenatal and neonatal problems, head circumference, muscle tone, EEG and MRI results, dysmorphic features, eye abnormalities, early development, language and comprehension, behavioral characteristics, and additional clinical problems. In addition, the mutations were classified into five groups according to the severity of symptoms. The study showed wide genotypic and phenotypic variability in patients with CTNNB1 Syndrome. The most common moderate-severe phenotype manifested in facial dysmorphisms, microcephaly, various motor disabilities, language and cognitive impairments, and behavioral abnormalities (e.g., autistic-like or aggressive behavior). Nonsense and missense mutations occurring in exons 14 and 15 were classified in the normal clinical outcome category/group because they had presented an otherwise normal phenotype, except for eye abnormalities. A milder phenotype was also observed with missense and nonsense mutations in exon 13. The autosomal dominant CTNNB1 Syndrome encompasses a wide spectrum of clinical features, ranging from normal to severe. While mutations cannot be more generally categorized by location, it is generally observed that the C-terminal protein region (exons 13, 14, 15) correlates with a milder phenotype.
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  • 文章类型: Case Reports
    Ververi-Brady syndrome (VBS), first reported in 2018, is characterized by intellectual disability, speech delay, and mild dysmorphic facial features. VBS has been linked to de novo loss-of-function variants in the glutamine-rich protein 1 (QRICH1) on chromosome 3p21 and was reported until lately in only five individuals. Four additional cases have just been described substantiating the notion that children with VBS are mildly dysmorphic, mildly to moderately intellectually disabled, have linear growth shortage, are picky eaters, and have notable attention and social behavioral deficits. We describe a new patient and review the clinical and genetic information, on all previously reported VBS cases. The child here reported is noted for maladaptive behavior, sensory hypersensitivity, and slow linear growth. He is mainly hyperactive, distractible, impulsive, and inattentive. His speech, initially delayed, is fair and his verbal comprehension age adequate.
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  • 文章类型: Journal Article
    背景:细胞色素P4502C19(CYP2C19)多态性与卒中或短暂性脑缺血发作(TIA)患者神经功能恶化之间的关联尚未完全了解。因此,我们对前瞻性队列研究进行了系统评价和荟萃分析,以量化这种关联.
    方法:PubMed,科克伦图书馆,摘录医学数据库,搜索了截至2019年4月发表的《中国国家知识基础设施》和《万方》数据库。纳入了报道CYP2C19多态性与卒中/TIA患者神经功能恶化之间关联的前瞻性队列研究。作者提取并汇总了风险比(RR)和95%置信区间(CI)的数据。遵循系统评价和荟萃分析指南的首选报告项目。
    结果:纳入了12项符合条件的研究。12项研究报告了CYP2C19*2,*3个功能丧失等位基因,5项研究报告了CYP2C19*17个功能获得等位基因。与非运营商相比,CYP2C19*2,*3功能丧失等位基因的携带者具有显著较高的神经系统恶化风险(RR,1.63;95CI,1.32-2.02)。相反,CYP2C19*17功能获得等位基因的携带者神经系统恶化的风险显着降低(RR,0.520;95CI,0.393-0.689)与非运营商相比。
    结论:该荟萃分析表明,与中风或TIA患者的非携带者相比,CYP2C19*2,*3功能丧失等位基因的携带者神经系统恶化的风险增加。此外,CYP2C19*17功能获得等位基因可以降低神经系统恶化的风险。
    BACKGROUND: The association between cytochrome P450 2C19 (CYP2C19) polymorphisms and neurological deterioration in stroke or transient ischemic attack (TIA) patients is not completely understood. Hence, we performed a systematic review and meta-analysis of prospective cohort studies to quantify this association.
    METHODS: PubMed, Cochrane Library, Excerpta Medica Database, China National Knowledge Infrastructure and WanFang databases were searched for studies published up to April 2019. Prospective cohort studies that reported an association between CYP2C19 polymorphisms and neurological deterioration in stroke/TIA patients were included. Data on risk ratio (RR) and 95% confidence intervals (CI) were extracted and pooled by the authors. Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines were followed.
    RESULTS: Twelve eligible studies were included. Twelve studies reported CYP2C19∗2, ∗3 loss-of-function alleles and 5 studies reported CYP2C19∗17 gain-of-function allele. Compared to non-carriers, carriers of CYP2C19∗2, ∗3 loss-of-function alleles had a significantly higher risk of neurological deterioration (RR, 1.63; 95%CI, 1.32-2.02). Conversely, carriers of CYP2C19∗17 gain-of-function allele had a significantly lower risk of neurological deterioration (RR, 0.520; 95%CI, 0.393-0.689) compared to non-carriers.
    CONCLUSIONS: This meta-analysis demonstrated that the carriers of CYP2C19∗2, ∗3 loss-of-function alleles have an increased risk of neurological deterioration compared to non-carriers in stroke or TIA patients. Additionally, CYP2C19∗17 gain-of-function allele can reduce the risk of neurological deterioration.
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  • 文章类型: Case Reports
    Heterozygous variants in USP9X are associated with female-restricted X-linked mental retardation (MRXS99F), a rare syndrome characterized by neurodevelopmental delay, intellectual disability (ID), and a wide variety of additional congenital anomalies. Here, we report a girl harboring a novel de novo loss-of-function variant in USP9X (c.4091delinsAG, p.Thr1364Lysfs*7), and literature review revealed novel prenatal features associated with MRXS99F, expanding the genotypic and phenotypic landscape of the syndrome. It is important to consider X-linked diseases in girls with ID and perform directed molecular investigation to provide correct diagnosis and prognosis.
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  • 文章类型: Case Reports
    ATP6V0A2-related cutis laxa, also known as autosomal recessive cutis laxa type 2A (ARCL2A), is a subtype of hereditary cutis laxa originally characterized by skin, skeletal, and neurological involvement, and a combined defect of N-glycosylation and O-glycosylation. The associated clinical spectrum subsequently expanded to a less severe phenotype dominated by cutaneous involvement. At the moment, ARCL2A was described in a few case reports and series only. An Italian adult woman ARCL2A with a phenotype restricted to skin and the two novel c.3G>C and c.1101dup ATP6V0A2 variants has been reported. A systematic literature review allowed us to identify 69 additional individuals from 64 families. Available data were scrutinized in order to describe the clinical and molecular variability of ARCL2A. About 78.3% of known variants were predicted null alleles, while 11 were missense and 2 affected noncanonical splice sites. Age at ascertainment appeared as the unique phenotypic discriminator with earlier age more commonly associated with facial dysmorphism (p .02), high/cleft palate (p .005), intellectual disability/global developmental delay (p .013), and seizures (p .024). No specific genotype-phenotype correlations were identified. This work confirmed the existence of an attenuated phenotype associated with ATP6V0A2 biallelic variants and offers an updated critique to the clinical and molecular variability of ARCL2A.
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  • 文章类型: Case Reports
    We describe two sporadic and two familial cases with loss-of-function variants in PRPS1, which is located on the X chromosome and encodes phosphoribosyl pyrophosphate synthetase 1 (PRS-1). We illustrate the clinical variability associated with decreased PRS-1 activity, ranging from mild isolated hearing loss to severe encephalopathy. One of the variants we identified has already been reported with a phenotype similar to our patient\'s, whereas the other three were unknown. The clinical and biochemical information we provide will hopefully contribute to gain insight into the correlation between genotype and phenotype of this rare condition, both in females and in males. Moreover, our observation of a new family in which hemizygous males display hearing loss without any neurological or ophthalmological symptoms prompts us to suggest analysing PRPS1 in cases of isolated hearing loss. Eventually, PRPS1 variants should be considered as a differential diagnosis of mitochondrial disorders.
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  • 文章类型: Research Support, Non-U.S. Gov\'t
    Background: Zeta-Chain Associated Protein Kinase 70 kDa (ZAP-70) deficiency is a rare combined immunodeficiency (CID) caused by recessive homozygous/compound heterozygous loss-of-function mutations in the ZAP70 gene. Patients with ZAP-70 deficiency present with a variety of clinical manifestations, particularly recurrent respiratory infections and cutaneous involvements. Therefore, a systematic review of ZAP-70 deficiency is helpful to achieve a comprehensive view of this disease. Methods: We searched PubMed, Web of Science, and Scopus databases for all reported ZAP-70 deficient patients and screened against the described eligibility criteria. A total of 49 ZAP-70 deficient patients were identified from 33 articles. For all patients, demographic, clinical, immunologic, and molecular data were collected. Results: ZAP-70 deficient patients have been reported in the literature with a broad spectrum of clinical manifestations including recurrent respiratory infections (81.8%), cutaneous involvement (57.9%), lymphoproliferation (32.4%), autoimmunity (19.4%), enteropathy (18.4%), and increased risk of malignancies (8.1%). The predominant immunologic phenotype was low CD8+ T cell counts (97.9%). Immunologic profiling showed defective antibody production (57%) and decreased lymphocyte responses to mitogenic stimuli such as phytohemagglutinin (PHA) (95%). Mutations of the ZAP70 gene were located throughout the gene, and there was no mutational hotspot. However, most of the mutations were located in the kinase domain. Hematopoietic stem cell transplantation (HSCT) was applied as the major curative treatment in 25 (51%) of the patients, 18 patients survived transplantation, while two patients died and three required a second transplant in order to achieve full remission. Conclusion: Newborns with consanguineous parents, positive family history of CID, and low CD8+ T cell counts should be considered for ZAP-70 deficiency screening, since early diagnosis and treatment with HSCT can lead to a more favorable outcome. Based on the current evidence, there is no genotype-phenotype correlation in ZAP-70 deficient patients.
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