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Journal of Medical Genetics Dec 2023Alström syndrome (ALMS; #203800) is an ultrarare monogenic recessive disease. This syndrome is associated with variants in the gene, which encodes a... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Alström syndrome (ALMS; #203800) is an ultrarare monogenic recessive disease. This syndrome is associated with variants in the gene, which encodes a centrosome-associated protein involved in the regulation of several ciliary and extraciliary processes, such as centrosome cohesion, apoptosis, cell cycle control and receptor trafficking. The type of variant associated with ALMS is mostly complete loss-of-function variants (97%) and they are mainly located in exons 8, 10 and 16 of the gene. Other studies in the literature have tried to establish a genotype-phenotype correlation in this syndrome with limited success. The difficulty in recruiting a large cohort in rare diseases is the main barrier to conducting this type of study.
METHODS
In this study we collected all cases of ALMS published to date. We created a database of patients who had a genetic diagnosis and an individualised clinical history. Lastly, we attempted to establish a genotype-phenotype correlation using the truncation site of the patient's longest allele as a grouping criteria.
RESULTS
We collected a total of 357 patients, of whom 227 had complete clinical information, complete genetic diagnosis and meta-information on sex and age. We have seen that there are five variants with high frequency, with p.(Arg2722Ter) being the most common variant, with 28 alleles. No gender differences in disease progression were detected. Finally, truncating variants in exon 10 seem to be correlated with a higher prevalence of liver disorders in patients with ALMS.
CONCLUSION
Pathogenic variants in exon 10 of the gene were associated with a higher prevalence of liver disease. However, the location of the variant in the gene does not have a major impact on the phenotype developed by the patient.
Topics: Humans; Alstrom Syndrome; Cell Cycle Proteins; Phenotype; Exons; Genetic Association Studies
PubMed: 37321834
DOI: 10.1136/jmg-2023-109175 -
Yonago Acta Medica May 2024Alström syndrome is a form of inherited obesity caused by a single gene abnormality and is inherited as an autosomal recessive trait. It is characterised by a variety... (Review)
Review
Alström syndrome is a form of inherited obesity caused by a single gene abnormality and is inherited as an autosomal recessive trait. It is characterised by a variety of clinical manifestations, including progressive visual and hearing impairment, type 2 diabetes mellitus, dilated cardiomyopathy, and hepatic and renal dysfunction, in addition to obesity. Recent insights underline the pivotal involvement of the disease-associated gene () in cilia formation and function, leading to the classification of its clinical manifestations as a ciliopathy. This review delineates the diverse clinical indicators defining the syndrome and elucidates its pathological underpinnings.
PubMed: 38803594
DOI: 10.33160/yam.2024.05.010 -
BMC Medical Genomics Apr 2024Syndromic ciliopathies are a group of congenital disorders characterized by broad clinical and genetic overlap, including obesity, visual problems, skeletal anomalies,...
BACKGROUND
Syndromic ciliopathies are a group of congenital disorders characterized by broad clinical and genetic overlap, including obesity, visual problems, skeletal anomalies, mental retardation, and renal diseases. The hallmark of the pathophysiology among these disorders is defective ciliary functions or formation. Many different genes have been implicated in the pathogenesis of these diseases, but some patients still remain unclear about their genotypes.
METHODS
The aim of this study was to identify the genetic causes in patients with syndromic ciliopathy. Patients suspected of or meeting clinical diagnostic criteria for any type of syndromic ciliopathy were recruited at a single diagnostic medical center in Southern Taiwan. Whole exome sequencing (WES) was employed to identify their genotypes and elucidate the mutation spectrum in Taiwanese patients with syndromic ciliopathy. Clinical information was collected at the time of patient enrollment.
RESULTS
A total of 14 cases were molecularly diagnosed with syndromic ciliopathy. Among these cases, 10 had Bardet-Biedl syndrome (BBS), comprising eight BBS2 patients and two BBS7 patients. Additionally, two cases were diagnosed with Alström syndrome, one with Oral-facial-digital syndrome type 14, and another with Joubert syndrome type 10. A total of 4 novel variants were identified. A recurrent splice site mutation, BBS2: c.534 + 1G > T, was present in all eight BBS2 patients, suggesting a founder effect. One BBS2 patient with homozygous c.534 + 1G > T mutations carried a third ciliopathic allele, TTC21B: c.264_267dupTAGA, a nonsense mutation resulting in a premature stop codon and protein truncation.
CONCLUSIONS
Whole exome sequencing (WES) assists in identifying molecular pathogenic variants in ciliopathic patients, as well as the genetic hotspot mutations in specific populations. It should be considered as the first-line genetic testing for heterogeneous disorders characterized by the involvement of multiple genes and diverse clinical manifestations.
Topics: Humans; Male; Female; Taiwan; Ciliopathies; Child; Child, Preschool; Mutation; Exome Sequencing; Bardet-Biedl Syndrome; Adolescent; Infant; Abnormalities, Multiple; Retina; Syndrome; Cilia; Eye Abnormalities; Cerebellum; Proteins; Kidney Diseases, Cystic
PubMed: 38671463
DOI: 10.1186/s12920-024-01880-0 -
Brazilian Journal of Otorhinolaryngology 2024To report two new variants of ALMS1 gene and to discuss the audiological evolution and clinical phenotype in two pairs of siblings with Alström syndrome.
OBJECTIVES
To report two new variants of ALMS1 gene and to discuss the audiological evolution and clinical phenotype in two pairs of siblings with Alström syndrome.
REPORT
This paper is a multi-disciplinary diagnostic evaluation, with genetic and audiological analysis that aims to report two new variants of the ALMS1 gene and to discuss the audiological evolution and clinical phenotype in a case series of patients with familial Alström syndrome. Therefore, we describe 4 cases presenting a complete audiometric profile of two pairs of unrelated siblings, to provide a better understanding of this very rare disease. Additionally, the present study identified two heterozygous mutations in the ALMS1 gene.
CONCLUSION
This Clinical Capsule Report highlights the importance of audiological monitoring throughout the development of patients with Alström syndrome. The two variants found were not previously reported in the literature, which expands the spectrum of ALMS1 variants in Alström syndrome.
Topics: Child, Preschool; Female; Humans; Male; Alstrom Syndrome; Cell Cycle Proteins; Mutation; Phenotype; Infant; Adult
PubMed: 38428329
DOI: 10.1016/j.bjorl.2024.101402 -
Proceedings of the National Academy of... Jun 2023Retinitis pigmentosa (RP) is an ocular disease characterized by the loss of night vision, followed by the loss of daylight vision. Daylight vision is initiated in the...
Retinitis pigmentosa (RP) is an ocular disease characterized by the loss of night vision, followed by the loss of daylight vision. Daylight vision is initiated in the retina by cone photoreceptors, which are gradually lost in RP, often as bystanders in a disease process that initiates in their neighboring rod photoreceptors. Using physiological assays, we investigated the timing of cone electroretinogram (ERG) decline in RP mouse models. A correlation between the time of loss of the cone ERG and the loss of rods was found. To investigate a potential role of the visual chromophore supply in this loss, mouse mutants with alterations in the regeneration of the retinal chromophore, 11- retinal, were examined. Reducing chromophore supply via mutations in or resulted in greater cone function and survival in a RP mouse model. Conversely, overexpression of and , genes that can drive the regeneration of the chromophore, led to greater cone degeneration. These data suggest that abnormally high chromophore supply to cones upon the loss of rods is toxic to cones, and that a potential therapy in at least some forms of RP is to slow the turnover and/or reduce the level of visual chromophore in the retina.
Topics: Mice; Animals; Retina; Retinal Cone Photoreceptor Cells; Retinal Rod Photoreceptor Cells; Retinitis Pigmentosa; Color Vision; Disease Models, Animal
PubMed: 37252956
DOI: 10.1073/pnas.2217885120 -
Molecular Genetics & Genomic Medicine Jan 2024Alström syndrome (AS) represents an exceptionally rare genetic disorder characterized by a constellation of features including cardiomyopathy, progressive hearing and... (Review)
Review
BACKGROUND
Alström syndrome (AS) represents an exceptionally rare genetic disorder characterized by a constellation of features including cardiomyopathy, progressive hearing and vision impairment, as well as obesity. This study seeks to elucidate the genetic underpinnings of this syndrome within the Saudi Arabian population.
METHODS
Employing an extended family cohort, we conducted an exhaustive molecular genetic assessment to delineate the presence of Alström syndrome. Additionally, we conducted an extensive review of existing literature from Saudi population to contextualize our findings within the broader understanding of the disorder in our country.
RESULTS
Within our studied extended family, we identified two individuals harboring the homozygous pathogenic mutation (c.2729C>G) in the ALMS1 gene [NM_015120.4:c.2729C>G (p.Ser910*)]. Notably, carrier status was observed in the parents, whereas some siblings exhibited typical alleles while others were carriers of the mutation. Intriguingly, a review of the literature unveiled six distinct reports documenting a total of 20 Alström syndrome patients within the Saudi Arabian population, each presenting with distinct novel mutations.
CONCLUSIONS
In cases featuring cardiomyopathy, obesity, and progressive hearing and vision loss, Alström syndrome merits inclusion within the differential diagnosis. To confirm the diagnosis, molecular genetic assessment of the ALMS1 gene is imperative, offering definitive clarity amidst the complex clinical presentation. This investigation reinforces the importance of genetic scrutiny for precise diagnosis and highlights the unique genetic landscape of Alström syndrome within the Saudi Arabian population.
Topics: Humans; Alstrom Syndrome; Cell Cycle Proteins; Extended Family; Saudi Arabia; Obesity; Mutation; Cardiomyopathies
PubMed: 37937857
DOI: 10.1002/mgg3.2314 -
CircALMS1 Alleviates Pulmonary Microvascular Endothelial Cell Dysfunction in Pulmonary Hypertension.Journal of the American Heart... Mar 2024Circular RNAs can serve as regulators influencing the development of pulmonary hypertension (PH). However, their function in pulmonary vascular intimal injury remains...
BACKGROUND
Circular RNAs can serve as regulators influencing the development of pulmonary hypertension (PH). However, their function in pulmonary vascular intimal injury remains undefined. Thus, we aimed to identify specifically expressed circular RNAs in pulmonary microvascular endothelial cells (PMECs) under hypoxia and PH.
METHODS AND RESULTS
Deep RNA sequencing and quantitative real-time polymerase chain reaction revealed that circALMS1 (circular RNA Alstrom syndrome protein 1) was reduced in human PMECs under hypoxia (<0.0001). Molecular biology and histopathology experiments were used to elucidate the roles of circALMS1 in regulating PMEC dysfunction among patients with PH. The circALMS1 expression was decreased in the plasma of patients with PH (=0.0315). Patients with lower circALMS1 levels had higher risk of death (=0.0006). Moreover, the circALMS1 overexpression of adeno-associated viruses improved right ventricular function and reduced pulmonary vascular remodeling in monocrotaline-PH and sugen/hypoxia-PH rats (<0.05). Furthermore, circALMS1 overexpression promoted apoptosis and inhibited PMEC proliferation and migration under hypoxia by directly downregulating miR-17-3p (<0.05). Dual luciferase assay confirmed the direct binding of circALMS1 to miR-17-3p and miR-17-3p binding to its target gene YT521-B homology domain-containing family protein 2 (YTHDF2) (<0.05). The YTHDF2 levels were also downregulated in hypoxic PMECs (<0.01). The small interfering RNA YTHDF2 reversed the effects of miR-17-3p inhibitors on PMEC proliferation, migration, and apoptosis. Finally, the results indicated that, although YTHDF2, as an N(6)-methyladenosine reader protein, contributes to the degradation of many circular RNAs, it could not regulate the circALMS1 levels in PMECs (=0.9721).
CONCLUSIONS
Our study sheds new light on circALMS1-regulated dysfunction of PMECs by the miR-17-3p/YTHDF2 pathway under hypoxia and provides insights into the underlying pathogenesis of PH.
Topics: Humans; Rats; Animals; Hypertension, Pulmonary; MicroRNAs; Endothelial Cells; RNA, Circular; Pulmonary Artery; Hypoxia; Cell Proliferation
PubMed: 38497483
DOI: 10.1161/JAHA.123.031867 -
Journal of Pediatric Genetics Jun 2024Alstrom's syndrome (AS) is an autosomal recessively inherited multisystemic disorder that falls under the umbrella of ciliopathy. It is characterized by poor vision,...
Alstrom's syndrome (AS) is an autosomal recessively inherited multisystemic disorder that falls under the umbrella of ciliopathy. It is characterized by poor vision, hearing impairment, cardiomyopathy, childhood obesity, diabetes mellitus type 2, dyslipidemia, pulmonary, hepatic, and renal failure besides systemic fibrosis. Biallelic pathogenic variants in gene cause AS. Retrospective study (1990-2017) included 12 Saudi patients with AS based on their phenotype, biochemical markers, and genotype. The study was approved by Fisal Specialist Hospital and Research Centre, Riyadh (RAC number 2131129) on October 2, 2012. This study showed clinical and genetic heterogeneity; six patients showed a founder mutation (IVS18-2A > T in exon 19), whereas six others showed private mutations. AS in Saudi Arabia is underdiagnosed probably because of its variable clinical manifestations. We report 12 Saudi patients with AS to enhance the awareness about this syndrome.
PubMed: 38721579
DOI: 10.1055/s-0041-1740369 -
Biology Direct Dec 2023Alström syndrome (ALMS) is a rare autosomal recessive disease that is associated with mutations in ALMS1 gene. The main clinical manifestations of ALMS are retinal...
BACKGROUND
Alström syndrome (ALMS) is a rare autosomal recessive disease that is associated with mutations in ALMS1 gene. The main clinical manifestations of ALMS are retinal dystrophy, obesity, type 2 diabetes mellitus, dilated cardiomyopathy and multi-organ fibrosis, characteristic in kidneys and liver. Depletion of the protein encoded by ALMS1 has been associated with the alteration of different processes regulated via the primary cilium, such as the NOTCH or TGF-β signalling pathways. However, the cellular impact of these deregulated pathways in the absence of ALMS1 remains unknown.
METHODS
In this study, we integrated RNA-seq and proteomic analysis to determine the gene expression profile of hTERT-BJ-5ta ALMS1 knockout fibroblasts after TGF-β stimulation. In addition, we studied alterations in cross-signalling between the TGF-β pathway and the AKT pathway in this cell line.
RESULTS
We found that ALMS1 depletion affects the TGF-β pathway and its cross-signalling with other pathways such as PI3K/AKT, EGFR1 or p53. In addition, alterations associated with ALMS1 depletion clustered around the processes of extracellular matrix regulation and lipid metabolism in both the transcriptome and proteome. By studying the enriched pathways of common genes differentially expressed in the transcriptome and proteome, collagen fibril organisation, β-oxidation of fatty acids and eicosanoid metabolism emerged as key processes altered by the absence of ALMS1. Finally, an overactivation of the AKT pathway was determined in the absence of ALMS1 that could be explained by a decrease in PTEN gene expression.
CONCLUSION
ALMS1 deficiency disrupts cross-signalling between the TGF-β pathway and other dependent pathways in hTERT-BJ-5ta cells. Furthermore, altered cross-signalling impacts the regulation of extracellular matrix-related processes and fatty acid metabolism, and leads to over-activation of the AKT pathway.
Topics: Humans; Lipid Metabolism; Diabetes Mellitus, Type 2; Proteome; Phosphatidylinositol 3-Kinases; Proteomics; Proto-Oncogene Proteins c-akt; Cell Cycle Proteins; Alstrom Syndrome; Transforming Growth Factor beta; Extracellular Matrix
PubMed: 38062477
DOI: 10.1186/s13062-023-00441-2 -
Genes Sep 2023Bardet-Biedl syndrome (BBS) and Alström syndrome (ALMS) are rare multisystem diseases with an autosomal recessive mode of inheritance and genetic heterogeneity,...
Bardet-Biedl syndrome (BBS) and Alström syndrome (ALMS) are rare multisystem diseases with an autosomal recessive mode of inheritance and genetic heterogeneity, characterized by visual impairment, hearing impairment, cardiomyopathy, childhood obesity, and insulin resistance. The purpose of our study was to evaluate the indicators of nervous system changes occurring in patients with ALMS and BBS using optical coherence tomography (OCT) and magnetic resonance spectroscopy (MRS) methods compared to a group of healthy subjects. The OCT results showed significantly lower macular thickness in the patient group compared to the control group ( = 0.002). The MRS study observed differences in metabolite levels between the study and control groups in brain areas such as the cerebellum, thalamus, and white matter. After summing the concentrations from all areas, statistically significant results were obtained for N-acetylaspartate, total N-acetylaspartate, and total creatine. Concentrations of these metabolites were reduced in ALMS/BBS patients by 38% ( = 0.0004), 35% ( = 0.0008), and 28% ( = 0.0005), respectively. Our results may help to understand the pathophysiology of these rare diseases and identify strategies for new therapies.
Topics: Humans; Child; Bardet-Biedl Syndrome; Pediatric Obesity; Alstrom Syndrome; Brain
PubMed: 37761924
DOI: 10.3390/genes14091784