neurodevelopmental disorder neurodevelopmental disorder neurodevelopmental disorders are a group of mental disorders that affect the development of the nervous system, leading to abnormal brain function which may affect emotion, learning ability, self-control, and memory. the effects of neurodevelopmental disorders tend to last for a person's lifetime. neurodevelopmental disorderspecialtypsychiatry, neurology types neurodevelopmental disorders are impairments of the growth and development of the brain and/or central nervous system. a narrower use of the term refers to a disorder of brain function that affects emotion, learning ability, self-control and memory which unfolds as an individual develops and grows. according to the dsm-5, the neurodevelopmental disorders include the following: attention deficit hyperactivity disorder (adhd) dld - developmental language disorder (formerly known as sli- specific language impairment) communication, speech, or language disorders, expressive language disorder, fluency disorder, social (pragmatic) communication disorder, and speech sound disorder. autism spectrum disorder (asd) intellectual disabilities (ids) or intellectual development disorder (idd, previously called mental retardation) and global developmental delay (gdd) motor disorders including developmental coordination disorder, stereotypic movement disorder, and tic disorders (such as tourette's syndrome), and cas - apraxia of speech neurogenetic disorders, such as fragile x syndrome, down syndrome, rett syndrome, hypogonadotropic hypogonadal syndromes specific learning disorders, like dyslexia or dyscalculia. traumatic brain injury (including congenital injuries such as those that cause cerebral palsy) and disorders due to neurotoxicants including minamata disease caused by mercury, behavioral disorders including conduct disorder etc. caused by other heavy metals, such as lead, chromium, platinum etc., hydrocarbons like dioxin, pbdes and pcbs, medications and illegal drugs, like cocaine, radioactive metals like po210(which is found in cigarettes), and others. fetal alcohol spectrum disorders (fasd) can exhibit a combination of the above, most commonly adhd, because of this, fasd is usually under-diagnosed, yet it is estimated that about 1 in 20 people may be affected. currently being researched there are neurodevelopmental research projects examining potential new classifications of disorders including: nonverbal learning disorder (nld or nvld), a neurodevelopmental disorder thought to be linked to white matter in the right hemisphere of the brain and generally considered to include (a) low visuospatial intelligence; (b) discrepancy between verbal and visuospatial intelligence; (c) visuoconstructive and fine-motor coordination skills; (d) visuospatial memory tasks; (e) reading better than mathematical achievement; and (f) socioemotional skills. while nonverbal learning disorder is not categorized in the icd or dsm as an discrete classification, "the majority of researchers and clinicians agree that the profile of nld clearly exists (but see spreen, 2011, for an exception), but they disagree on the need for a specific clinical category and on the criteria for its identification." presentation consequences the multitude of neurodevelopmental disorders span a wide range of associated symptoms and severity, resulting in different degrees of mental, emotional, physical, and economic consequences for individuals, and in turn families, social groups, and society. causes the development of the nervous system is tightly regulated and timed; it is influenced by both genetic programs and the environment. any significant deviation from the normal developmental trajectory early in life can result in missing or abnormal neuronal architecture or connectivity. because of the temporal and spatial complexity of the developmental trajectory, there are many potential causes of neurodevelopmental disorders that may affect different areas of the nervous system at different times and ages. these range from social deprivation, genetic and metabolic diseases, immune disorders, infectious diseases, nutritional factors, physical trauma, and toxic and environmental factors. some neurodevelopmental disorders, such as autism and other pervasive developmental disorders, are considered multifactorial syndromes which have many causes that converge to a more specific neurodevelopmental manifestation. social deprivation deprivation from social and emotional care causes severe delays in brain and cognitive development. studies with children growing up in romanian orphanages during nicolae ceauşescu's regime reveal profound effects of social deprivation and language deprivation on the developing brain. these effects are time-dependent. the longer children stayed in negligent institutional care, the greater the consequences. by contrast, adoption at an early age mitigated some of the effects of earlier institutionalization (abnormal psychology). genetic disorders main article: genetic disorder a child with down syndrome a prominent example of a genetically determined neurodevelopmental disorder is trisomy 21, also known as down syndrome. this disorder usually results from an extra chromosome 21, although in uncommon instances it is related to other chromosomal abnormalities such as translocation of the genetic material. it is characterized by short stature, epicanthal (eyelid) folds, abnormal fingerprints, and palm prints, heart defects, poor muscle tone (delay of neurological development), and intellectual disabilities (delay of intellectual development). less commonly known genetically determined neurodevelopmental disorders include fragile x syndrome. fragile x syndrome was first described in 1943 by martin and bell, studying persons with family history of sex-linked "mental defects". rett syndrome, another x-linked disorder, produces severe functional limitations. williams syndrome is caused by small deletions of genetic material from chromosome 7. the most common recurrent copy number variant disorder is 22q11.2 deletion syndrome (formerly digeorge or velocardiofacial syndrome), followed by prader-willi syndrome and angelman syndrome. immune dysfunction main article: immune-mediated disease immune reactions during pregnancy, both maternal and of the developing child, may produce neurodevelopmental disorders. one typical immune reaction in infants and children is pandas, or pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection. another disorder is sydenham's chorea, which results in more abnormal movements of the body and fewer psychological sequellae. both are immune reactions against brain tissue that follow infection by streptococcus bacteria. susceptibility to these immune diseases may be genetically determined, so sometimes several family members may have one or both of them following an epidemic of strep infection. infectious diseases systemic infections can result in neurodevelopmental consequences, when they occur in infancy and childhood of humans, but would not be called a primary neurodevelopmental disorder. for example hiv infections of the head and brain, like brain abscesses, meningitis or encephalitis have a high risk of causing neurodevelopmental problems and eventually a disorder. for example, measles can progress to subacute sclerosing panencephalitis. a number of infectious diseases can be transmitted congenitally (either before or at birth), and can cause serious neurodevelopmental problems, as for example the viruses hsv, cmv, rubella (congenital rubella syndrome), zika virus, or bacteria like treponema pallidum in congenital syphilis, which may progress to neurosyphilis if it remains untreated. protozoa like plasmodium or toxoplasma which can cause congenital toxoplasmosis with multiple cysts in the brain and other organs, leading to a variety of neurological deficits. some cases of schizophrenia may be related to congenital infections, though the majority are of unknown causes. metabolic disorders metabolic disorders in either the mother or the child can cause neurodevelopmental disorders. two examples are diabetes mellitus (a multifactorial disorder) and phenylketonuria (an inborn error of metabolism). many such inherited diseases may directly affect the child's metabolism and neural development but less commonly they can indirectly affect the child during gestation. 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