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Behavioral and Brain Functions : BBF May 2022Genetic variants of DCX, COMT and FMR1 have been linked to neurodevelopmental disorders related to intellectual disability and social behavior. In this systematic review... (Review)
Review
Genetic variants of DCX, COMT and FMR1 have been linked to neurodevelopmental disorders related to intellectual disability and social behavior. In this systematic review we examine the roles of the DCX, COMT and FMR1 genes in the context of hippocampal neurogenesis with respect to these disorders with the aim of identifying important hubs and signaling pathways that may bridge these conditions. Taken together our findings indicate that factors connecting DCX, COMT, and FMR1 in intellectual disability and social behavior may converge at Wnt signaling, neuron migration, and axon and dendrite morphogenesis. Data derived from genomic research has identified a multitude of genes that are linked to brain disorders and developmental differences. Information about where and how these genes function and cooperate is lagging behind. The approach used here may help to shed light on the biological underpinnings in which key genes interface and may prove useful for the testing of specific hypotheses.
Topics: Catechol O-Methyltransferase; Cognitive Dysfunction; Fragile X Mental Retardation Protein; Hippocampus; Humans; Intellectual Disability; Neurogenesis; Social Behavior
PubMed: 35590332
DOI: 10.1186/s12993-022-00191-7 -
Environmental Health Perspectives Jun 2000This paper sets a framework for the discussion of neurotoxicity as a potentially major contributor to the etiology of many types of mental retardation and developmental... (Review)
Review
This paper sets a framework for the discussion of neurotoxicity as a potentially major contributor to the etiology of many types of mental retardation and developmental disabilities. In the past the literatures on developmental neurotoxicology and on mental retardation have evolved independently, yet we know that the developing brain is a target for neurotoxicity in the developing central nervous system through many stages of pregnancy as well as during infancy and early childhood. Our definitions and theories of mental retardation and developmental disabilities affect the models of neurotoxicity we espouse. For instance, models of developmental risk in neurotoxicology have guided environmental regulation to reduce the likelihood of neurotoxic effects. On the other hand, models of developmental risk for mental retardation aim not only at primary prevention,but also at secondary and tertiary prevention through early intervention. In the future, dynamic models of neuroplasticity based on the study of gene-brain-behavior relationships are likely to guide our views of developmental neurotoxicology and prevention of mental retardation and other disabilities.
Topics: Developmental Disabilities; Embryonic and Fetal Development; Environmental Health; Female; Humans; Intellectual Disability; Neurotoxins; Pregnancy; Risk Assessment; Xenobiotics
PubMed: 10852834
DOI: 10.1289/ehp.00108s3395 -
Journal of Medical Genetics Jun 2003In recent years, subtelomeric rearrangements have been identified as a major cause of mental retardation and/or malformation syndromes. So far, over 2500 subjects with... (Review)
Review
In recent years, subtelomeric rearrangements have been identified as a major cause of mental retardation and/or malformation syndromes. So far, over 2500 subjects with mental retardation have been tested and reported of whom approximately 5% appeared to have a subtelomeric rearrangement. In this review, the clinical aspects of each known (submicroscopic) subtelomeric deletion will be presented and the various methods available for detecting subtelomeric abnormalities will be discussed. Not only will the patients and their families benefit from a good collection and report of the various telomeric abnormalities and their clinical phenotype, but it will also give more insight into the aetiology of mental retardation and malformation syndromes.
Topics: Chromosome Deletion; Female; Humans; In Situ Hybridization, Fluorescence; Intellectual Disability; Male; Telomere
PubMed: 12807958
DOI: 10.1136/jmg.40.6.385 -
BMC Public Health Apr 2021Disability in India is associated with increasing non-communicable diseases, rising longevity, and increasing accidents and injuries. Though studies have examined...
BACKGROUND
Disability in India is associated with increasing non-communicable diseases, rising longevity, and increasing accidents and injuries. Though studies have examined prevalence, patterns, and socioeconomic correlates of disability, no attempt has been made in estimating age of onset of disability in India.
OBJECTIVE
This paper investigates the economic gradient of age of onset of locomotor, visual, hearing, speech, mental retardation, mental illness, and other disabilities in India.
METHOD
We use nationally representative data of 106,894 disabled individuals from the 76th round of National Sample Survey (NSS), 2018. Descriptive statistics, kernel density, Kaplan-Meier survival curves, and linear regression models are used in the analysis.
RESULT
The disability rate in India was 2184 per 100,000 persons. The disability rate was highest for locomotor (1353) followed by hearing (296), visual (234), speech (228), mental retardation (158), and mental illness (131). Over 85% of mental retardation and 80% of speech disabilities occur at birth, while 82% of locomotor and 81% of visual disabilities occur after birth. Among those who had disability after birth, the median age for mental retardation was 2 years followed by mental illness (28 years), speech (29 years), locomotor (42 years), visual (55 years), and 56 years for hearing disability. Adjusting for socioeconomic covariates, the age of onset of locomotor and speech disabilities among the poorest individuals were 7 and 11 years earlier than the richest, respectively.
CONCLUSION
The economic gradient of onset of locomotive and speech disabilities are strong. The age of onset of disability was earliest for mental retardation followed by mental illness and speech disability.
Topics: Child; Child, Preschool; Disabled Persons; Humans; India; Infant, Newborn; Intellectual Disability; Poverty; Prevalence
PubMed: 33882902
DOI: 10.1186/s12889-021-10826-5 -
Prilozi (Makedonska Akademija Na... Dec 2023Cerebellar ataxia, mental retardation, and disequilibrium syndrome (CAMRQ) is a genetically and clinically heterogeneous disorder with four described subtypes. Autosomal...
Cerebellar ataxia, mental retardation, and disequilibrium syndrome (CAMRQ) is a genetically and clinically heterogeneous disorder with four described subtypes. Autosomal recessive syndrome of cerebellar ataxia, mental retardation, and disequilibrium type 4 (CAMRQ4) is caused by mutations in the gene. We report an 8-year-old boy with choreoathetosis, hypotonia, without the ability to keep his head up and profound mental retardation. There was quadrupedal locomotion, as well. MRI of the brain revealed a hypotrophy of the corpus callosum, diffuse white matter reduction, widespread delayed myelination and ventriculomegaly. Trio whole-exome sequencing revealed compound heterozygosity in the gene consisting of a known variant c.1756C>T (p.Arg586*) inherited from the mother and a novel variant c.691_701delCTGATGAAGTT (p.Leu231fs) inherited from the father. CAMRQ type 4 has been found in about 50 patients. To the best of our knowledge, this is the first reported patient with CAMRQ4 with these gene variants. The clinical presentation is severe.
Topics: Male; Humans; Child; Cerebellar Ataxia; Intellectual Disability; Brain; Mutation
PubMed: 38109455
DOI: 10.2478/prilozi-2023-0051 -
Cold Spring Harbor Perspectives in... Oct 2012This article describes three rare syndromes in which the presence of α-thalassemia provided an important clue to the molecular basis of the underlying condition. It...
This article describes three rare syndromes in which the presence of α-thalassemia provided an important clue to the molecular basis of the underlying condition. It exemplifies how rare diseases allied with careful clinical observation can lead to important biological principles. Two of the syndromes, ATR-16 and ATR-X, are characterized by α-thalassemia in association with multiple developmental abnormalities including mental retardation. The third condition, ATMDS, is an acquired disorder in which α-thalassemia arises in the context of myelodysplasia. Intriguingly, mutations in the chromatin remodeling factor, ATRX, are common to both ATR-X syndrome and ATMDS.
Topics: Chromatin Assembly and Disassembly; Humans; Intellectual Disability; Mental Retardation, X-Linked; Mutation; Myelodysplastic Syndromes; alpha-Thalassemia
PubMed: 23028133
DOI: 10.1101/cshperspect.a011759 -
Fly 2009Mental retardation--known more commonly nowadays as intellectual disability--is a severe neurological condition affecting up to 3% of the general population. As a result... (Review)
Review
Mental retardation--known more commonly nowadays as intellectual disability--is a severe neurological condition affecting up to 3% of the general population. As a result of the analysis of familial cases and recent advances in clinical genetic testing, great strides have been made in our understanding of the genetic etiologies of mental retardation. Nonetheless, no treatment is currently clinically available to patients suffering from intellectual disability. Several animal models have been used in the study of memory and cognition. Established paradigms in Drosophila have recently captured cognitive defects in fly mutants for orthologs of genes involved in human intellectual disability. We review here three protocols designed to understand the molecular genetic basis of learning and memory in Drosophila and the genes identified so far with relation to mental retardation. In addition, we explore the mental retardation genes for which evidence of neuronal dysfunction other than memory has been established in Drosophila. Finally, we summarize the findings in Drosophila for mental retardation genes for which no neuronal information is yet available. All in all, this review illustrates the impressive overlap between genes identified in human mental retardation and genes involved in physiological learning and memory.
Topics: Animals; Behavior, Animal; Drosophila; Female; Genes, Insect; Humans; Intellectual Disability; Learning; Male; Memory; Models, Animal; Models, Psychological; Mutation; Phenotype; Species Specificity
PubMed: 19182539
DOI: 10.4161/fly.3.1.7812 -
Revista de NeurologiaTo present within the general field of the conditions causing mental retardation, the preventive strategies for specific application available at the present time. (Review)
Review
OBJECTIVE
To present within the general field of the conditions causing mental retardation, the preventive strategies for specific application available at the present time.
DEVELOPMENT
In spite of the fact that in the majority of cases of mental retardation the etiology is unknown, and for that reason, in them it is not possible to establish preventive strategies, within the last three decades, important research advances have helped to prevent thousands of cases of mental retardation of illnesses caused by Haemophilus influenzae B, measles encephalitis, Rh disease and severe jaundice in newborn infants, congenital hypothyroidism, phenylketonuria and congenital rubella; as well as removing lead from the environment, intervention programs for the proper use of seat belts, child safety seats, and motorcycle and bicycle helmets; early and adequate prenatal care, dietary supplementation with folic acid beginning before conception to reduce the risk of neural tube defects, avoidance of toxic substances during pregnancy like alcohol, and the use of newborn screening tests.
CONCLUSION
The primary and secondary prevention of conditions that cause mental retardation continue being a challenge. Require of a review of the present strategies, that frequently inform about the problem, but are not practice in an every day bases (ej. intake of alcohol during pregnancy, the universal use of seat belt and child safety seats during automobile travel). In the future we may have the possibility of prenatal gene therapy.
Topics: Central Nervous System Infections; Cognition; Diagnosis, Differential; Female; Humans; Intellectual Disability; Metabolism, Inborn Errors; Neuropsychological Tests; Pregnancy; Prognosis
PubMed: 12589608
DOI: No ID Found -
The Neuroscientist : a Review Journal... Oct 2009Fragile X syndrome (FXS) is the most common inherited form of mental retardation and a leading genetic cause of autism. There is increasing evidence in both FXS and... (Review)
Review
Fragile X syndrome (FXS) is the most common inherited form of mental retardation and a leading genetic cause of autism. There is increasing evidence in both FXS and other forms of autism that alterations in synapse number, structure, and function are associated and contribute to these prevalent diseases. FXS is caused by loss of function of the Fmr1 gene, which encodes the RNA binding protein, fragile X mental retardation protein (FMRP). Therefore, FXS is a tractable model to understand synaptic dysfunction in cognitive disorders. FMRP is present at synapses where it associates with mRNA and polyribosomes. Accumulating evidence finds roles for FMRP in synapse development, elimination, and plasticity. Here, the authors review the synaptic changes observed in FXS and try to relate these changes to what is known about the molecular function of FMRP. Recent advances in the understanding of the molecular and synaptic function of FMRP, as well as the consequences of its loss, have led to the development of novel therapeutic strategies for FXS.
Topics: Brain; Fragile X Mental Retardation Protein; Fragile X Syndrome; Humans; Intellectual Disability; Nerve Tissue Proteins; Neuronal Plasticity; Protein Transport; RNA, Messenger; Receptors, Metabotropic Glutamate; Synapses
PubMed: 19325170
DOI: 10.1177/1073858409333075 -
American Family Physician Jun 2006Persons with mental retardation are living longer and integrating into their communities. Primary medical care of persons with mental retardation should involve... (Review)
Review
Persons with mental retardation are living longer and integrating into their communities. Primary medical care of persons with mental retardation should involve continuity of care, maintenance of comprehensive treatment documentation, routine periodic health screening, and an understanding of the unique medical and behavioral disorders common to this population. Office visits can be successful if physicians familiarize patients with the office and staff, plan for difficult behaviors, and administer mild sedation when appropriate. Some syndromes that cause mental retardation have specific medical and behavioral features. Health issues in these patients include respiratory problems, gastrointestinal disorders, challenging behaviors, and neurologic conditions. Some commonly overlooked health concerns are sexuality, sexually transmitted diseases, and end-of-life decisions.
Topics: Constipation; Gastrointestinal Diseases; Humans; Informed Consent; Intellectual Disability; Mental Competency; Musculoskeletal Diseases; Oral Hygiene; Pain; Primary Health Care; Seizures; Skin Care; Sleep Apnea, Obstructive; Women's Health
PubMed: 16836033
DOI: No ID Found