Neurodevelopmental disorders are a group of 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 entire lifetime.
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.
The neurodevelopmental disorders currently considered, recognised and/or acknowledged to be as such are:
Intellectual disability (ID) or intellectual and developmental disability (IDD), previously called mental retardation
Specific learning disorders, like Dyslexia or Dyscalculia.
Autism spectrum disorders, such as Asperger's syndrome or Autistic Disorder
Motor disorders including developmental coordination disorder and stereotypic movement disorder
Tic disorders including Tourette's syndrome
Traumatic brain injury (including congenital injuries such as those that cause cerebral palsy)
Communication, speech and language disorders
Genetic disorders, such as fragile-X syndrome, Down syndrome, attention deficit hyperactivity disorder, schizophrenia, schizotypal disorder, hypogonadotropic hypogonadal syndromes
Disorders due to neurotoxicants like fetal alcohol spectrum disorder, 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 and others.
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.
Neurodevelopmental disorders are diagnosed by evaluating the presence of characteristic symptoms or behaviors in a child, typically after a parent, guardian, teacher, or other responsible adult has raised concerns to a doctor.
Neurodevelopmental disorders may also be confirmed by genetic testing. Traditionally, disease related genetic and genomic factors are detected by karyotype analysis, which detects clinically significant genetic abnormalities for 5% of children with a diagnosed disorder. As of 2017, chromosomal microarray analysis (CMA) was proposed to replace karyotyping because of its ability to detect smaller chromosome abnormalities and copy-number variants, leading to greater diagnostic yield in about 20% of cases. The American College of Medical Genetics and Genomics and the American Academy of Pediatrics recommend CMA as standard of care in the US.
Journal of Brain Research