Rubinstein–Taybi syndrome: clinical and molecular overview

2007 ◽  
Vol 9 (23) ◽  
pp. 1-16 ◽  
Author(s):  
Jeroen H. Roelfsema ◽  
Dorien J.M. Peters
Keyword(s):  
Mental Retardation ◽  
Growth Retardation ◽  
Molecular Mechanisms ◽  
Clinical Presentation ◽  
Point Mutations ◽  
Affected Individual ◽  
Histone Acetyltransferases ◽  
Signalling Pathways ◽  
Large Deletions ◽  
Strong Homology

Rubinstein–Taybi syndrome is characterised by mental retardation, growth retardation and a particular dysmorphology. The syndrome is rare, with a frequency of approximately one affected individual in 100 000 newborns. Mutations in two genes –CREBBPandEP300– have been identified to cause the syndrome. These two genes show strong homology and encode histone acetyltransferases (HATs), which are transcriptional co-activators involved in many signalling pathways. Loss of HAT activity is sufficient to account for the phenomena seen in Rubinstein–Taybi patients. Although some mutations found inCREBBPare translocations, inversions and large deletions, most are point mutations or small deletions and insertions. Mutations inEP300are comparatively rare. Extensive screening of patients has revealed mutations inCREBBPandEP300in around 50% of cases. The cause of the syndrome in the remaining patients remains to be identified, but other genes could also be involved. Here, we describe the clinical presentation of Rubinstein–Taybi syndrome, review the mutation spectrum and discuss the current understanding of causative molecular mechanisms.

The Variable Expression of a Novel MBD5 Gene Frameshift Mutation in an Italian Family

2020 ◽  
Author(s):  
Alfredo Orrico ◽  
Lucia Galli ◽  
Maja Rossi ◽  
Ambra Cortesi ◽  
Marta Mazzi ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Novel Mutation ◽  
Point Mutations ◽  
Autism Spectrum ◽  
Cognitive Disability ◽  
Dominant Type ◽  
Variable Expression ◽  
Large Deletions ◽  
Pathogenic Variants ◽  
Autosomal Dominant Type

AbstractHaploinsufficiency of the methyl-CpG-binding domain protein 5 (MBD5) gene is reported as a cause of an autosomal dominant type of cognitive disability (MRD1) and autism spectrum disorder through large deletions involving multiple genes or point mutations, ultimately leading to haploinsufficiency in both cases. However, relatively few reports have been published on the phenotypical spectrum resulting from point mutations.We report here on a novel heterozygous frameshift variant in the MBD5 gene [c.2579del; p.(Lys860Argfs*11)] in a family in which the typical signs associated with pathogenic variants were expressed with different degrees of severity in the clinical presentation of the carrier individuals.Our findings, adding a novel mutation to the mutational spectrum, further support the relevance of the MBD5 gene as one of the main molecular mechanisms involved in the pathogenesis of intellectual disability and contribute to the characterization of the genotype–phenotype correlations.

Jansky-Bielschowsky syndrome, a lysosomal disease: First diagnosed cash in Oman

1992 ◽  
Vol 50 (1) ◽  
pp. 632-633
Author(s):  
Line Buhl ◽  
David Muirhead
Keyword(s):  
Mental Retardation ◽  
Clinical Picture ◽  
Neurological Disorder ◽  
Clinical Presentation ◽  
Neuronal Ceroid Lipofuscinosis ◽  
Infantile Form ◽  
Lysosomal Disease ◽  
Juvenile Form ◽  
Progressive Encephalopathy ◽  
Lysosomal Diseases

There are four lysosomal diseases of which the neuronal ceroid lipofuscinosis is the rarest. The clinical presentation and their characteric abnormal ultrastructure subdivide them into four types. These are known as the Infantile form (Santavuori-Haltia), Late infantile form (Jansky-Bielschowsky), Juvenile form (Batten-Spielmeyer-Voght) and the Adult form (Kuph's).An 8 year old Omani girl presented wth myclonic jerks since the age of 4 years, with progressive encephalopathy, mental retardation, ataxia and loss of vision. An ophthalmoscopy was performed followed by rectal suction biopsies (fig. 1). A previous sibling had died of an undiagnosed neurological disorder with a similar clinical picture.

Myocardial Infarction in Systemic Lupus Erythematosus – the Sex Specific Risk Profile

2020 ◽  
Vol 26 ◽  
Author(s):  
Marija Vavlukis ◽  
Daniela Pop-Gjorceva ◽  
Lidija Poposka ◽  
Emilija Sandevska ◽  
Sasko Kedev
Keyword(s):  
Myocardial Infarction ◽  
Systemic Lupus Erythematosus ◽  
Cardiovascular Risk ◽  
Coronary Artery ◽  
Young Women ◽  
Lupus Erythematosus ◽  
Molecular Mechanisms ◽  
Clinical Presentation ◽  
Systemic Lupus ◽  
Antiinflammatory Therapy

Background: Accelerated atherosclerosis is widely present in patients with systemic lupus erythematosus. Objective: The aim of this review is to analyze the relationship between systemic lupus erythematosus and cardiovascular diseases, with the emphasis on acute myocardial infarction. Results: Various molecular mechanisms triggered by infection/inflammation are responsible for endothelial dysfunction and development of atherosclerosis at an earlier age. Contributing factor is the cumulative effect of traditional cardiovascular risk factors interaction with disease related characteristics. Myocardial infarction rates are 2- to 10-fold higher compared to the general population. Young women have the highest relative risk, however, men carry at least 3- fold higher risk than women. Coronary involvement varies from normal coronary artery with thrombosis, coronary microartery vasculitis, coronary arteritis, and coronary atherosclerosis. Typical clinical presentation is observed in men and older women, while atypical is more frequent in young women. Treatment is guided by the underlying mechanism, engaging invasive procedures alone, or accompanied with immunosuppressive and/or antiinflammatory therapy. There are significant gender differences in pathophysiology and clinical presentation. However, they receive the same therapeutic treatments. Conclusion: Systemic lupus erythematosus is a major contributor to atherosclerotic and non-atherosclerotic mechanisms involved in the development of myocardial infarction, which should be taken into account during therapeutic treatment. Although Systemic lupus erythematosus per se is a “female” disease, males are at increased cardiovascular risk and worse outcome. Method: We conducted a literature review through PubMed and Cochrane, using key words: SLE, atherosclerosis, atherothrombosis, coronary artery disease, myocardial infarction, prognosis, sex specifics.

scholarly journals The Phosphatidylserine Receptor TIM-1 Enhances Authentic Chikungunya Virus Cell Entry

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1828
Author(s):  
Jared Kirui ◽  
Yara Abidine ◽  
Annasara Lenman ◽  
Koushikul Islam ◽  
Yong-Dae Gwon ◽  
...  
Keyword(s):  
Chikungunya Virus ◽  
Molecular Mechanisms ◽  
Rna Virus ◽  
Ectopic Expression ◽  
Point Mutations ◽  
Cell Entry ◽  
Target Cells ◽  
Human Hepatoma Cells ◽  
Chikv Infection ◽  
Phosphatidylserine Receptor

Chikungunya virus (CHIKV) is a re-emerging, mosquito-transmitted, enveloped positive stranded RNA virus. Chikungunya fever is characterized by acute and chronic debilitating arthritis. Although multiple host factors have been shown to enhance CHIKV infection, the molecular mechanisms of cell entry and entry factors remain poorly understood. The phosphatidylserine-dependent receptors, T-cell immunoglobulin and mucin domain 1 (TIM-1) and Axl receptor tyrosine kinase (Axl), are transmembrane proteins that can serve as entry factors for enveloped viruses. Previous studies used pseudoviruses to delineate the role of TIM-1 and Axl in CHIKV entry. Conversely, here, we use the authentic CHIKV and cells ectopically expressing TIM-1 or Axl and demonstrate a role for TIM-1 in CHIKV infection. To further characterize TIM-1-dependent CHIKV infection, we generated cells expressing domain mutants of TIM-1. We show that point mutations in the phosphatidylserine binding site of TIM-1 lead to reduced binding, entry, and infection of CHIKV. Ectopic expression of TIM-1 renders immortalized keratinocytes permissive to CHIKV, whereas silencing of endogenously expressed TIM-1 in human hepatoma cells reduces CHIKV infection. Altogether, our findings indicate that, unlike Axl, TIM-1 readily promotes the productive entry of authentic CHIKV into target cells.

scholarly journals Maternal Uniparental Disomy of Chromosome 20 (UPD(20)mat) as Differential Diagnosis of Silver Russell Syndrome: Identification of Three New Cases

Genes ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 588
Author(s):  
Pierpaola Tannorella ◽  
Daniele Minervino ◽  
Sara Guzzetti ◽  
Alessandro Vimercati ◽  
Luciano Calzari ◽  
...  
Keyword(s):  
Growth Retardation ◽  
Molecular Mechanisms ◽  
Uniparental Disomy ◽  
Postnatal Growth ◽  
Molecular Diagnostic ◽  
Growth Delay ◽  
Molecular Defect ◽  
Maternal Uniparental Disomy ◽  
Feeding Difficulties ◽  
Silver Russell Syndrome

Silver Russell Syndrome (SRS, MIM #180860) is a rare growth retardation disorder in which clinical diagnosis is based on six features: pre- and postnatal growth failure, relative macrocephaly, prominent forehead, body asymmetry, and feeding difficulties (Netchine–Harbison clinical scoring system (NH-CSS)). The molecular mechanisms consist in (epi)genetic deregulations at multiple loci: the loss of methylation (LOM) at the paternal H19/IGF2:IG-DMR (chr11p15.5) (50%) and the maternal uniparental disomy of chromosome 7 (UPD(7)mat) (10%) are the most frequent causes. Thus far, about 40% of SRS remains undiagnosed, pointing to the need to define the rare mechanisms in such a consistent fraction of unsolved patients. Within a cohort of 176 SRS with an NH-CSS ≥ 3, a molecular diagnosis was disclosed in about 45%. Among the remaining patients, we identified in 3 probands (1.7%) with UPD(20)mat (Mulchandani–Bhoj–Conlin syndrome, OMIM #617352), a molecular mechanism deregulating the GNAS locus and described in 21 cases, characterized by severe feeding difficulties associated with failure to thrive, preterm birth, and intrauterine/postnatal growth retardation. Our patients share prominent forehead, feeding difficulties, postnatal growth delay, and advanced maternal age. Their clinical assessment and molecular diagnostic flowchart contribute to better define the characteristics of this rare imprinting disorder and to rank UPD(20)mat as the fourth most common pathogenic molecular defect causative of SRS.

DLX6-AS1: a putative lncRNA candidate in multiple human cancers

2021 ◽  
Vol 23 ◽  
Author(s):  
Mohsen Sheykhhasan ◽  
Yaghoub Ahmadyousefi ◽  
Reihaneh Seyedebrahimi ◽  
Hamid Tanzadehpanah ◽  
Hamed Manoochehri ◽  
...  
Keyword(s):  
Cancer Progression ◽  
Critical Analysis ◽  
Molecular Mechanisms ◽  
Signalling Pathways ◽  
Biological Functions ◽  
Initial Development ◽  
Human Cancers ◽  
Expression Of Genes ◽  
Non Coding Rnas ◽  
Research Studies

Abstract Long non-coding RNAs (lncRNAs) have important roles in regulating the expression of genes and act as biomarkers in the initial development of different cancers. Increasing research studies have verified that dysregulation of lncRNAs occurs in various pathological processes including tumorigenesis and cancer progression. Among the different lncRNAs, DLX6-AS1 has been reported to act as an oncogene in the development and prognoses of different cancers, by affecting many different signalling pathways. This review summarises and analyses the recent research studies describing the biological functions of DLX6-AS1, its overall effect on signalling pathways and the molecular mechanisms underlying its action on the expression of genes in multiple human cancers. Our critical analysis suggests that different signalling pathways associated to this lncRNA may be used as a biomarker for diagnosis, or targets of treatment in cancers.

Painful, reappearing eruption in a medically complex 4-year-old

2021 ◽  
Vol 14 (2) ◽  
pp. e239310
Author(s):  
Meredith Sooy ◽  
Rachel L Randell ◽  
Dmitry Tchapyjnikov ◽  
Klaus Werner ◽  
Kristina Nazareth-Pidgeon
Keyword(s):  
Skin Biopsy ◽  
Growth Retardation ◽  
Clinical Presentation ◽  
Heart Defects ◽  
Pathogenic Mutation ◽  
Rare Disorder ◽  
Frequent Episodes ◽  
First Case

A 4-year-old boy with atypical, complete DiGeorge and CHARGE (coloboma, heart defects, atresia choanae, growth retardation, genital abnormalities and ear abnormalities) syndromes presented with frequent episodes of a painful, markedly erythematous eruption associated with swelling. Evaluation revealed non-specific findings on skin biopsy at the time of eruption and no pathogenic mutation in the SCN9A gene. The patient was diagnosed with secondary erythromelalgia based on clinical presentation. Erythromelalgia is a rare disorder characterised by recurrent episodes of pain and erythema typically affecting the distal extremities. This case represents the first case of erythromelalgia in the setting of DiGeorge and CHARGE syndromes.

scholarly journals Activation-induced Deaminase (AID)-directed Hypermutation in the Immunoglobulin Sμ Region

2002 ◽  
Vol 195 (4) ◽  
pp. 529-534 ◽  
Author(s):  
Hitoshi Nagaoka ◽  
Masamichi Muramatsu ◽  
Namiko Yamamura ◽  
Kazuo Kinoshita ◽  
Tasuku Honjo
Keyword(s):  
B Lymphocytes ◽  
Single Molecule ◽  
Dna Cleavage ◽  
Somatic Hypermutation ◽  
Point Mutations ◽  
Genetic Alterations ◽  
Variable Regions ◽  
Class Switch ◽  
Large Deletions ◽  
Activation Induced Deaminase

Somatic hypermutation (SHM) and class switch recombination (CSR) cause distinct genetic alterations at different regions of immunoglobulin genes in B lymphocytes: point mutations in variable regions and large deletions in S regions, respectively. Yet both depend on activation-induced deaminase (AID), the function of which in the two reactions has been an enigma. Here we report that B cell stimulation which induces CSR but not SHM, leads to AID-dependent accumulation of SHM-like point mutations in the switch μ region, uncoupled with CSR. These findings strongly suggest that AID itself or a single molecule generated by RNA editing function of AID may mediate a common step of SHM and CSR, which is likely to be involved in DNA cleavage.

scholarly journals The Primary Causes of Muscle Dysfunction Associated with the Point Mutations in Tpm3.12; Conformational Analysis of Mutant Proteins as a Tool for Classification of Myopathies

2018 ◽  
Vol 19 (12) ◽  
pp. 3975 ◽  
Author(s):  
Yurii Borovikov ◽  
Olga Karpicheva ◽  
Armen Simonyan ◽  
Stanislava Avrova ◽  
Elena Rogozovets ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Molecular Mechanisms ◽  
Fiber Type ◽  
Point Mutations ◽  
Nemaline Myopathy ◽  
Muscle Dysfunction ◽  
Thin Filaments ◽  
Mutant Proteins ◽  
Strong Binding ◽  
Genes Encoding

Point mutations in genes encoding isoforms of skeletal muscle tropomyosin may cause nemaline myopathy, cap myopathy (Cap), congenital fiber-type disproportion (CFTD), and distal arthrogryposis. The molecular mechanisms of muscle dysfunction in these diseases remain unclear. We studied the effect of the E173A, R90P, E150A, and A155T myopathy-causing substitutions in γ-tropomyosin (Tpm3.12) on the position of tropomyosin in thin filaments, and the conformational state of actin monomers and myosin heads at different stages of the ATPase cycle using polarized fluorescence microscopy. The E173A, R90P, and E150A mutations produced abnormally large displacement of tropomyosin to the inner domains of actin and an increase in the number of myosin heads in strong-binding state at low and high Ca2+, which is characteristic of CFTD. On the contrary, the A155T mutation caused a decrease in the amount of such heads at high Ca2+ which is typical for mutations associated with Cap. An increase in the number of the myosin heads in strong-binding state at low Ca2+ was observed for all mutations associated with high Ca2+-sensitivity. Comparison between the typical conformational changes in mutant proteins associated with different myopathies observed with α-, β-, and γ-tropomyosins demonstrated the possibility of using such changes as tests for identifying the diseases.

Sign in / Sign up

Export Citation Format

Share Document