DEVELOPMENTAL DISORDERS Chapter C.1 Xiaoyan Ke & Jing Liu INTELLECTUAL DISABILITY This publication is intended for professionals training or practicing in mental health and not for the general public. (Data from Persaud TVN, Chudley AE, Skalko RG, eds: Abnormal numbers of the sex chromosomes are relatively common and can be detected by examination of the sex chromatin (X chromosome) or the fluorescence reactions of the Y chromosomes. Different organs have different periods of susceptibility during embryogenesis (Fig. At certain critical periods during pregnancy, embryos are more susceptible to agents or factors causing abnormal development than at other times. Recent findings: Treatment of developmental disorders may include medication and specialized training to … The opinions expressed are those of the authors and do not necessarily represent the views of the Editor or IACAPAP. In light of the recognition of the importance of folic acid in the prevention of neural tube defects, it is possible that the high incidence of anencephaly in Ireland resulted from poor nutrition in pregnant women during the winter. Other pervasive developmental disorder symptoms and sign. Researchers have gained new insights into how maternal infections during pregnancy can lead to developmental disorders in children. 2015 Mar;56(3):251-73. doi: 10.1111/jcpp.12374. The basic information is encoded in the genes, but as the genetic instructions unfold, the developing structures or organs are subjected to microenvironmental or macroenvironmental influences that either are compatible with or interfere with normal development. According to most studies, approximately 2% to 3% of all living newborns show at least one recognizable congenital malformation. Epub 2014 Dec 12. The period of maximal susceptibility to abnormal development occurs between weeks 3 and 8, which is the period when most of the major organs and body regions are first being established. have allowed the following generalization: Insults to the embryo during the first 3 weeks of embryogenesis (the early period before organogenesis begins) are unlikely to result in defective development because they either kill the embryo or are compensated for by the powerful regulatory properties of the early embryo. Three autosomal trisomies produce infants with characteristic associations of anomalies. A good example of the former is thalidomide, which has a very narrow and well-defined danger zone during the embryonic period (4 to 6 weeks). Such children have a difficult time understanding simple sentences and directions, or fail to name simple objects. Would you like email updates of new search results? What is the leading cause of stuttering in adults? National Center for Biotechnology Information, Unable to load your collection due to an error, Unable to load your delegates due to an error. 1p. Purely environmental causes can interfere with embryological processes in the face of a normal genotype. Rare copy number variations affecting the synaptic gene DMXL2 in neurodevelopmental disorders. One possibility is that a single teratogen acted on the primordia of several organs during susceptible periods of development. Folic acid supplementation in the diet of women of childbearing age significantly reduces the incidence of neural tube defects, such as anencephaly. Typically, a developing organ has a curve of susceptibility to teratogenic influences similar to that illustrated in Figure 8.5. USA.gov. Epub 2020 Apr 1. Developmental Disorders Causes, Mechanisms, and Patterns. October 2005; Trends in Cognitive Sciences 9(10) :465-466; DOI: 10.1016/j.tics.2005.08.003. Although medical embryology textbooks traditionally cover principally structural defects—congenital malformations—there is a continuum between purely biochemical abnormalities and defects that are manifested as abnormal structures. Taking pediatric health into consideration, developmental and behavioral issues can arise out of genetic causes, anatomical defects, or adverse environmental factors. The results of many investigations have allowed the following generalization: Insults to the embryo during the first 3 weeks of embryogenesis (the early period before organogenesis begins) are unlikely to result in defective development because they either kill the embryo or are compensated for by the powerful regulatory properties of the early embryo. Monosomy (the lack of one member of a chromosome pair) and trisomy (a triplet instead of the normal chromosome pair) are typically the result of nondisjunction during meiosis (see Fig. In other cases, environment and genetics interact. Authors: Michael S. C. Thomas. NIH Developmental disorders, including intellectual disability, autism and attention deficit hyperactivity disorder (ADHD), are neuropsychiatric disorders that manifest in early childhood as deviations from the normal development. principally structural defects—congenital malformations—there is a continuum between purely biochemical abnormalities and defects that are manifested as abnormal structures. Thalidomide, which is an inhibitor of tumor necrosis factor-α, is still a drug of choice in the treatment of leprosy and multiple myeloma. A Cross-Disorder Method to Identify Novel Candidate Genes for Developmental Brain Disorders. Auteur ISAGER (T.) DNK. Fjorden Hospital. These cases were concentrated in West Germany and Australia because the drug was commonly sold in these locations. Penetrance (the degree of manifestation) of an abnormal gene or expression of one component of a genetically multifactorial cascade can sometimes be profoundly affected by environmental conditions. Thalidomide is a very effective sedative that was widely used in West Germany, Australia, and other countries during the late 1950s. Psychopathology. Extensive studies in the past 30 years have established that cyclin-dependent kinases (CDKs) exert many diverse, important functions in a number of molecular and cellular processes that are at play during development. 8.2). Epub 2018 Sep 8. Developmental Disorders - Chapter Summary. Cleft lip and cleft palate are common. Another is amelia, in which a limb is entirely missing. Such individuals, who are said to have Turner’s syndrome, exhibit a female phenotype, but the gonads are sterile. They may involve dysfunction in attention, memory, perception, language, problem-solving, or social interaction. Early representations of some malformed infants are remarkable in their anatomical accuracy, and it is often possible to diagnose specific conditions or syndromes from the ancient art (Fig. With the decline in infant mortality caused by infectious diseases and nutritional problems, congenital malformations now rank high among the causes of infant mortality (currently >20%), and increasing percentages (≤30%) of infants admitted to neonatology or pediatric units come as a result of various forms of genetic diseases or congenital defects. Similar to what is the case for intellectual disability, recent genetic studies indicate a large degree of genetic heterogeneity for autism and ADHD. 8.9) in children born to women older than 35 years of age. over the generations. These cases were concentrated in West Germany and Australia because the drug was commonly sold in these locations. Despite the high number of causative or contributing genes, functional studies of these genes indicate a large degree of convergence into a smaller number of neurobiological pathways. Difficulty Relating to People, Objects, and Events; Difficulty With Changes in Routine or Familiar Surroundings; Problems With Using and Understanding Language Research into the causes of developmental disorders has identified 285 genes linked to these conditions, including 28 newly-associated genes. 2012 May;53(5):510-8. doi: 10.1111/j.1469-7610.2011.02478.x. DNK. Despite considerable research since the 1960s, the cause of at least 50% of human congenital malformations remains unknown (Fig. Other conditions are related to paternal age (see Fig. 1.7). This continuum includes defects that constitute abnormal structure, function, metabolism, and behavior. Such a simplified view of susceptible periods does not take into account, however, the possibility that a teratogen or some other harmful influence may be applied at an early stage of development, but not be expressed as a developmental disturbance until later during embryogenesis. When seen in humans or animals, malformations were often interpreted as omens of good or evil. Bayés M, Ramos JA, Cormand B, Hervas-Zúñiga A, del Campo M, Duran-Tauleria E, Ribasés M, Vilella-Cuadrada E, de Diego-Otero Y, Casas-Brugué M, Estivill X. Rev Neurol. Neurodevelopmental disorders are neurologically based conditions that can interfere with the acquisition, retention, or application of specific skills or sets of information. However, in the past 5 years major advances have been made in the identification of specific genetic … The primary disorders are Autism/Autistic Disorder, Asperger's Syndrome and Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS). Anencephaly (Fig. These arise during cell division, especially meiosis. 8.8). Click to share on Twitter (Opens in new window), Click to share on Facebook (Opens in new window), Click to share on Google+ (Opens in new window), Presurgical Functional MappingAndrew C. Papanicolaou, Roozbeh Rezaie, Shalini Narayana, Marina Kilintari, Asim F. Choudhri, Frederick A. Boop, and James W. Wheless, the Child With SeizureDon K. Mathew and Lawrence D. Morton, and Pharmacologic Consequences of SeizuresShilpa D. Kadam and Michael V. Johnston, Self-Limited EpilepsiesDouglas R. Nordli, Jr., Colin D. Ferrie, and Chrysostomos P. Panayiotopoulos, in Epilepsy: A Network and Neurodevelopmental PerspectiveRaman Sankar and Edward C. Cooper, Hematology, Oncology and Palliative Medicine, Early representations of some malformed infants are remarkable in their anatomical accuracy, and it is often possible to diagnose specific conditions or syndromes from the ancient art (, In the early nineteenth century, Etienne Geoffroy de St. Hilaire coined the term, The first of two major milestones in human teratology occurred in 1941, when Gregg in Australia recognized that the, Thalidomide is a very effective sedative that was widely used in West Germany, Australia, and other countries during the late 1950s. Race is a factor in many congenital malformations and a variety of diseases. Some individuals with monosomy of the sex chromosomes (45XO genotype) can survive, however (Fig. Clipboard, Search History, and several other advanced features are temporarily unavailable. 8.7). Soon, physicians began to see infants born with extremely rare birth defects. Table 8.4 summarizes some of the various types of deletions and duplications of the sex chromosomes. Prevalence and architecture of de novo mutations in developmental disorders. Please enable it to take advantage of the complete set of features! Generalized susceptibility curve to teratogenic influences by a single organ. 8.1B). Individuals with Down syndrome are typically mentally retarded and have a characteristic broad face with a flat nasal bridge, wide-set eyes, and prominent epicanthic folds. This fetus had not been exposed to thalidomide. Lin BD, Colas F, Nijman IJ, Medic J, Brands W, Parr JR, van Eijk KR, Klauck SM, Chiocchetti AG, Freitag CM, Maestrini E, Bacchelli E, Coon H, Vicente A, Oliveira G, Pagnamenta AT, Gallagher L, Ennis S, Anney R, Bourgeron T, Luykx JJ, Vorstman J. Transl Psychiatry. Get the latest public health information from CDC: https://www.coronavirus.gov, Get the latest research information from NIH: https://www.nih.gov/coronavirus, Find NCBI SARS-CoV-2 literature, sequence, and clinical content: https://www.ncbi.nlm.nih.gov/sars-cov-2/. HHS During the first days of the critical period, the susceptibility, measured as incidence or severity of malformation, increases sharply and then declines over a much longer period. | Understanding the pediatric psychiatric phenotype of 22q11.2 deletion syndrome. 8.4) occurs more frequently in January. Major causes of congenital malformations. Thalidomide was identified as the certain cause after some careful epidemiological detective work involving the collection of individual case reports and sorting of the drugs taken by mothers during the early period of their pregnancies. Although there is an overlap in the features of autism and PDDs, PDDs typically do not meet “all” the criteria for classical autism or Asperger’s syndrome. 2020 Aug;28(8):1098-1110. doi: 10.1038/s41431-020-0619-7. Purpose of review: At present, they are understood more at the level of statistical associations than as points of interference with specific developmental controls, but they are important clues to why development can go wrong. In addition to the disorders with known genetic cause that are associated with intellectual disability, autism and ADHD, an increasing number of novel recurrent structural variants are identified in association with these developmental disorders. The high percentage of unknown causes is the result of having to work retrospectively to identify the origin of a malformation. When the left and right hemispheres of the brain are not electrically balanced or synchronized, a diagnosis of functional disconnection syndrome is used. Chromosomal abnormalities are usually classified as structural or numerical errors. With the intense investigations that followed the thalidomide disaster, modern teratology came of age. Glostrup. Note the short stature, webbed neck, and infantile sexual characteristics. 2018 Oct;176(10):2182-2191. doi: 10.1002/ajmg.a.40387. High percentages of spontaneously aborted fetuses show major chromosomal abnormalities. NLM Each person has many thousands of genetic variations that can interact to influence how the brain develops. Some very complex organs, especially the brain and major sense organs, show prolonged periods of high susceptibility to disruption of normal development. Most developmental disabilities begin before a baby is born, but some can happen after birth because of injury, infection, or other factors. Major structural anomalies are unlikely to occur after the eighth week of pregnancy because, by this point, most organs have become well established. Congenital defects range from enzyme deficiencies caused by single nucleotide substitutions in the DNA molecule to very complex associations of gross anatomical abnormalities. Causes and Risk Factors. Certain other influences (e.g., intrauterine diseases, toxins) may result in the destruction of all or parts of structures that have already been formed. Polyploidy, especially triploidy, is likely to be caused by either the fertilization of an egg by more than one sperm or the lack of separation of a polar body during meiosis. Confirmation that mutations in DDX59 cause an autosomal recessive form of oral-facial-digital syndrome: Further delineation of the DDX59 phenotype in two new families. 1985, Liss increased incidences of congenital, well-known correlations exist between parental and. Novel therapeutic interventions well founded ):1098-1110. doi: 10.1038/s41398-020-00866-7 in genetics in developmental. Diagnosed in children during the first few years after birth first 1 or months... 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