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Results for “monogenic”

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At least 217 records · Page 12Linked to original sources
PubMed1993

Analysis of a terminal Xp22.3 deletion in a patient with six monogenic disorders: implications for the mapping of X linked ocular albinism.

The molecular characterisation of chromosomal aberrations in Xp22.3 has established the map position of several genes with mutations resulting in diverse phenotypes such as short stature (SS), chondrodysplasia punctata (CDPX), mental retardation (MRX), ichthyosis (XLI), and Kallmann syndrome (KAL). We describe the clinical symptoms of a patient with a complex syndrome compatible with all these conditions plus ocular albinism (OA1). He has a terminal Xp deletion of at least 10 Mb of DNA. Both the mother and sister of the patient are carriers of the deletion and show a number of traits seen in Turner's syndrome. The diagnosis of ocular albinism was confirmed in the patient and his mother, who shows iris translucency, patches and streaks of hypopigmentation in the fundus, and macromelanosomes in epidermal melanocytes. By comparative deletion mapping we can define a deletion interval, which locates the OA1 gene proximal to DXS143 and distal to DXS85, with the breakpoints providing valuable starting points for cloning strategies.

Abnormalities, Multiple↗
PubMed2005

Monogenic obesity in humans.

Until relatively recently, the small number of identifiable inherited human diseases associated with marked obesity were complex, pleiotropic developmental disorders, the molecular basis for which were entirely obscure. The molecular basis for many of these complex syndromes, such as Bardet Beidl syndrome, has been revealed, providing novel insights into processes essential for human hypothalamic function and energy balance. In addition to these discoveries, which were the fruits of positional cloning, the molecular constituents of the signaling pathways responsible for the control of mammalian energy homeostasis have been identified, largely through the study of natural or artificial mutations in mice. We discuss the increasing number of human disorders that result from genetic disruption of the leptin-melanocortin pathways that have been identified. Practical implications of these findings for genetic counseling, prognostication, and even therapy have already emerged.

Adolescent↗
PubMed2002

CADASIL: a monogenic condition causing stroke and subcortical vascular dementia.

Mutations in Notch3 are the cause of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), an inherited small vessel disease leading to subcortical strokes and vascular dementia. The phenotypic presentation is variable but remarkable for a high frequency of migraine with aura. Magnetic resonance images show a microangiopathic pattern of lesions. Prominent involvement of the temporopolar white matter and involvement of the temporopolar arcuate fibers are conspicuous findings seen in many patients. The underlying angiopathy is characterized by a unique type of ultrastructural basal lamina deposits and by degeneration of vascular smooth muscle cells which are the major source of Notch3 expression. In line with these findings there is evidence for a functional impairment of vascular smooth muscle cells. CADASIL has opened a new perspective in studying basic mechanisms of vessel wall degeneration and ischemic tissue damage related to small vessel disease.

Dementia, Multi-Infarct↗
PubMed2004

Inherited arrhythmogenic diseases: the complexity beyond monogenic disorders.

Twelve years after the identification of the molecular bases of the long-QT syndrome, it is now possible to express some considerations on the impact that genetic findings have had in the understanding of inherited arrhythmogenic diseases. Along with the excitement for the emerging data on genotype/phenotype correlation and for the development of the first recommendations for gene-specific management of patients, it is also important to acknowledge the unexpected complexity that has emerged. The focus of this article is to analyze the elusive aspects of the relationship between genetic defects and clinical manifestations and to propose some research directions that may provide the needed answers to move forward in the understanding of the genetics of heart rhythm abnormalities.

Ankyrins↗
PubMed2025

Uncovering the genetic architecture of ME/CFS: a precision approach reveals impact of rare monogenic variation.

BACKGROUND: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a disabling and heterogeneous disorder lacking validated biomarkers or targeted therapies. Clinical variability and elusive pathophysiology hinder progress toward effective diagnostics and treatment. Core symptoms include persistent fatigue, post-exertional malaise, unrefreshing sleep, cognitive dysfunction, and pain. We tested whether an individualized, “n-of-1” genomic and transcriptomic framework combined with comprehensive, participant-informed phenotyping could reveal molecular signatures unique to each patient. METHODS: Clinical-grade whole-genome sequencing was conducted in 31 affected individuals from 25 families, with RNA-seq performed on a subset (16 affected, 7 unaffected) using blood samples. Machine-learning assisted variant triage, transcript-aware damage prediction, and expert review identified pathogenic or likely pathogenic variants in 8 of 25 probands (32%) and 12 of 31 affected individuals (39%). RESULTS: Findings revealed marked genetic heterogeneity, including large-effect rare and more common variants. Implicated pathways included ATP generation, oxidative phosphorylation, fatty acid oxidation; regulation of glycolysis, amino acid and lipid turnover; ion and solute homeostasis; synaptic signaling, excitability, oxygen transport, and muscle integrity, resilience, and post-exertional recovery; previously implicated processes. Plausible modifiers influencing disease onset, severity, and relapsing–remitting patterns and possibly explaining intrafamilial variability and inconsistent findings across studies, were also identified. Despite gene-level diversity, downstream effects converged on impaired energy production, reduced stress resilience, and vulnerability to post-exertional metabolic failure; disruptions consistent with core ME/CFS symptoms of exertional intolerance, cognitive fog, and fatigue. CONCLUSIONS: Our findings support the hypothesis that at least a subset of ME/CFS cases represent distinct molecular disorders that converge on shared physiological pathways. Validation in larger, more diverse cohorts will be essential to test this hypothesis and establish generalizability, but increase size alone is unlikely to resolve causation in a disorder defined by rarity, heterogeneity, and molecular complexity. We suggest that progress will require experimental designs that integrate individual-level genomic data with deep, participant-informed deep phenotyping, capturing the combined effects of rare and common variants and environmental modifiers on disease expression and progression. We believe that an individualized precision medicine framework will uncover molecular drivers and modifiers of ME/CFS previously obscured by heterogeneity, enabling biologically informed stratification, improved trial design, biomarker discovery, and targeted interventions in this historically neglected condition.

Humans↗
PubMed2003

Minireview: human obesity-lessons from monogenic disorders.

Genetic influences on the determination of human fat mass are profound and powerful, a statement that does not conflict with the obvious influence of environmental factors that drive recent changes in the prevalence of obesity. The assertion of the importance of genetic factors has, until recently, largely been based on twin and adoption studies. However, in the last 6 yr, a number of human genes have been identified in which major missense or nonsense mutations are sufficient in themselves to result in severe early-onset obesity, usually associated with disruption of normal appetite control mechanisms. Progress in the identification of more common, subtler genetic variants that influence fat mass in larger numbers of people has been slower, but discernible. Human genetics will continue to make an invaluable contribution to the study of human obesity by identifying critical molecular components of the human energy balance regulatory systems, pointing the way toward more targeted and effective therapies and assisting the prediction of individual responses to environmental manipulations.

Furin↗
PubMed2002

Monogenic forms of obesity and diabetes mellitus.

Great progress has been made in identifying several genes and in understanding the molecular pathogenesis of inherited syndromes of obesity and diabetes mellitus (DM). In humans, mutations in leptin, leptin receptor, proopiomelanocortin (POMC), melanocortin-4 receptor (MC4R) and prohormone convertase 1 (PC1) have been described in patients with severe obesity. Most of these obesity disorders, with the exception of the MC4R mutations, exhibit recessive inheritance and a distinct phenotype with varying degrees of hypothalamic dysfunction, and they unravel the critical role of the central leptin and melanocortin pathways in human appetite control and energy homeostasis. Maturity onset diabetes of the young (MODY) is a genetically and clinically heterogeneous subtype of type 2 DM with early onset autosomal dominant inheritance and a primary defect in insulin secretion. To date, six MODY genes have been identified, the glucokinase gene and five beta cell-specific transcription factor genes, hepatocyte nuclear factor-1alpha (HNF-1alpha), HNF-1beta, HNF-4alpha, insulin promoter factor-1 (IPF-1) and NeuroD1/BETA2. Mitochondrial DNA mutations cause another form of DM with an insulin secretory defect that is commonly associated with neurosensory hearing impairment, and has strict maternal inheritance. At the other end of the spectrum are the inherited syndromes of insulin resistance that are caused by mutations in the insulin receptor gene and in the adipocyte-specific transcription factor PPARgamma. The advances in our knowledge of the phenotypic manifestations and underlying molecular mechanisms of genetic syndromes of obesity and DM raise expectations for molecular diagnosis, as well as for more etiological therapies and better prevention of the continuously increasing prevalence of obesity and DM in our modern societies.

Animals↗
PubMed2003

Gene therapy of monogenic and cardiovascular disorders.

The concept of gene therapy involves the introduction of genetic material into patient cells to cure or alleviate the symptoms of a disease by complementing a damaged gene or by giving the cell a new function. The belief that gene therapy would soon reach the clinic has been widely spread, frequently resulting in controversies when these expectations were not met. Nevertheless, over the last 10-year period, the experience from a number of clinical trials has taught us that gene transfer is technically feasible, but that the gene delivery vehicles, or vectors, for the transfer of genetic material are still suboptimal and that treatment may have severe side effects. This review will provide examples of different genetic disorders for which gene therapy is an option and has been attempted. It will also briefly discuss the existing vector systems and mention their advantages and drawbacks.

Adenoviruses, Human↗
PubMed2003

Pharmacogenomics of diuretic drugs: data on rare monogenic disorders and on polymorphisms and requirements for further research.

This review summarizes the current status of our knowledge about the role of pharmacogenetic variation in response to diuretics and suggests future research topics for the field. Genes with a role in the pharmacokinetics of most diuretics are renal drug transporters, especially OAT1, OAT3 and OCT2 (genes SLC22A6, SLC22A8 and SLC22A2) whereas variants in carbonic anhydrase (CA), cytochrome P450 enzymes and sulfotransferases are relevant only for specific substances. Genes on the pharmacodynamic side include the primary targets of thiazide, loop, K(+)-sparing and aldosterone antagonistic diuretics: NCC, NKCC2, ENaC and the mineralocorticoid receptor (genes SLC12A3, SLC12A1, SCNN1A, B, G and NR3C2). Rare variants of these proteins cause Gitelman's syndrome, Bartter's syndrome, Liddle's syndrome or pregnancy-induced hypertension. Polymorphisms in these and in associated proteins such as GNB3, alpha-adducin and angiotensin-converting enzyme (ACE) seem to be clinically relevant. In conclusion, first knowledge has evolved that efficacy of diuretic drugs may be determined by genetic polymorphisms in genes determining pharmacokinetics and pharmacodynamics of this drug class. In the future, the selection of a diuretic drug or the dosing schedules may be individually chosen based on pharmacogenetic parameters, however, many questions remain to be answered before this fantasy becomes reality.

Animals↗
PubMed1999

Primary hyperoxaluria type I: a model for multiple mutations in a monogenic disease within a distinct ethnic group.

Primary hyperoxaluria type 1 is an autosomal recessive inherited metabolic disease in which excessive oxalates are formed by the liver and excreted by the kidneys, causing a wide spectrum of phenotypes ranging from renal failure in infancy to mere renal stones in late adulthood. Mutations in the AGXT gene, encoding the liver-specific enzyme alanine:glyoxylate aminotransferase, are responsible for the disease. Seven mutations were detected in eight families in Israel. Four of these mutations are novel and three occur in children living in single-clan villages. The mutations are scattered along various exons (1, 4, 5, 7, 9, 10), and on different alleles comprising at least five different haplotypes. All but one of the mutations are in a homozygous pattern, reflecting the high rate of consanguinity in our patient population. Two affected brothers are homozygous for two different mutations expressed on the same allele. The patients comprise a distinct ethnic group (Israeli Arabs) residing in a confined geographic area. These results, which are supported by previous data, suggest for the first time that the phenomenon of multiple mutations in a relatively closed isolate is common and almost exclusive to the Israeli-Arab population. Potential mechanisms including selective advantage to heterozygotes, digenic inheritance, and the recent emergence of multiple mutations are discussed.

Arabs↗
PubMed1975

Broad-beta disease (type III hyperlipoproteinemia) in a large kindred. Evidence for a monogenic mechanism.

The inheritance of broad-beta disease (as specified by a type III lipoprotein pattern) has remained an enigma. Previous reports have variously implicated a single gene (autosomal dominant mode), a double dose of a single gene (autosomal recessive), two separate genes (mixed heterozygosity), or multiple genes (polygenic inheritance). The present study of a single, large kindred of 108 members spanning 4 generations provides evidence for an autosomal dominant mode, since at least 1 member of the first generation pair was normal, at least 5 of their 9 children had type III patterns, and at least 2 of these (whose spouses were normal) transmitted this pattern to their offspring. The findings also suggest that in this kindred the common occurrence of hypertriglyceridemia (in a type IV pattern) may represent either a variable phenotypic expression of the gene for broad-beta disease or the coexistence of a second, independent genetic lipid disorder.

Adult↗
PubMed2000

[Influence of population's genetic structure on the load size of monogenic hereditary diseases in Russia].

The paper presents the results of genetic and epidemiological study of populations in 5 Russian regions: the Kirov, Kostroma, and Bryansk Provinces, Krasnodar Territory, and the Republic of Mari El. The total size of the study population was over 1.5 million. Random inbreeding (Fst) in all Russian rural populations was significant and varied from 0.34 x 10(-3) to 7.6 x 10(-3). The prevalence rates for autosomal dominant (AD) disorders ranged from 0.22 to 3.93 per 1000. The load of autosomal recessive (AR) disorders varied from 0.17 to 2.01. The prevalence rates for AD and AR disorders was twice lower in the urban populations than those in the rural ones. The prevalence of X-linked recessive disorders was 0.33 per 1000 males. An analysis was made to examine the correlation between inherited diseases and Fst. The Pierson correlation coefficient was 0.81 and 0.87 for AD and AR disorders, respectively. The regression suggested that genetic differentiation of the populations with genes for hereditary disorders is partially related to gene drift. This suggestion was proved by genetic geographical mapping analysis. The similarity in the patterns of genetic distance distribution for all 3 genetic systems was revealed by the correlation coefficients between the maps for neutral genetic markers and the genes of AD and AR disorders which were equal to 0.67 and 0.65. There was the highest correlation coefficient between the maps of genetic distances for the genes of AD and AR disorders (Rs = 0.88).

Consanguinity↗
PubMedDate not supplied

[Gene therapy of monogenic hereditary diseases. Duchenne myodystrophy].

The paper highlights the new trends in gene therapy research area and clinical trials. It should be noted that the majority of firms involved in development of the scientific approaches to gene therapy are concentrated in the United States. The investments of the given companies on development and research of new genetic constructs also delivery systems make hundred millions dollars. The greatest part (more than 80%) of gene therapy clinical trials projects are also connected with the US research departments; the majority of them is related to tumor therapy. The advantages and drawbacks of the main methods of nucleic acids delivery to the cells are considered; diseases that are attempted to be treated using gene therapy methods are listed. A special attention of the review is devoted to the modern stand in research on cell and Duchenne muscular dystrophy (DMD) gene therapy, also brief description of basic results achieved in the authors laboratory is given. Basic original results of transfection of mdx mice (DMD biological models) with dystrophin cDNA delivered by gene gun, cationic liposomes, synthetic microspheres, viral olygopeptides and lactoferrine are summarized.

Animals↗