2. Definition and terminology
•Intellectual disability (ID) is a state of
functioning that typically begins in
childhood and is characterized by
limitations in intelligence and adaptive skills
•Mental Retardation to Intellectual
disability; DSM to ICD, AAIDD
3. adaptive functioning
Conceptual:
language, readin
g, writing, math,
reasoning, and
memory
Social:
interpersonal
communication
skills, the ability
to make and
retain
friendships
Practical:
personal
care, and
organizing
school tasks
4. Definition and terminology
•Intellectual disability (ID) is a state of
functioning that typically begins in
childhood and is characterized by
limitations in intelligence and adaptive skills
•Mental Retardation to Intellectual
disability; DSM to ICD, AAIDD
6. Global developmental delay
•Global developmental delay < Five
•motor (gross/fine), speech and
language, cognition, personal-social, and
daily living skills
12. Presentation and Evaluation
• Presentaion
• parental concerns; language delay, immature
behavior, immature self-help skills, or difficulty in
learning
• mild ID; school age / severely affected <two years /
genetic disorder; infancy
• gross motor
• Associated conditions; mental disorders, autism and
other behavioral disorders, seizure, motor
handicaps, structural abnormalities, dysmorphism, and
vision, hearing
• Endocrine; thyroid functions, short stature, and GH
deficiency
13. Presentation and Evaluation
•Evaluation-All children with ID
• history and physical examination
• developmental assessment
• vision and auditory screening
• Review of newborn screening results
• chromosomal microarray, CMA (genomic
microarray analysis)
• G-banded karyotype; Down
syndrome, chromosomal rearrangement, or
multiple miscarriages
14. Presentation and Evaluation
•Evaluation-Features requiring more
comprehensive evaluation
• parental consanguinity, prior unexplained
infant death, multiple miscarriages, or loss or
regression of developmental milestones
• MRI, metabolic testing, and genetics
consultation.
15. Presentation and Evaluation
•Evaluation-Features suggesting a specific
test
• Down, fragile X, or Rett syndrome or other
genetic disorders
• metabolic studies (serum amino acids, urine
organic acids, serum ammonia, and lactate) and
thyroid screen
• Biotinidase deficiency, Duchenne muscular
dystrophy, CNS malformation or
injury, seizures, and exposure to lead
16. Management, outcome, and
prevention
• strengthen the reduced function and to
minimize further cognitive deterioration.
• begin early and be sustained
• collaborative and multidisciplinary
• speech and language therapy, physical
therapy, family support, behavioral
intervention, and educational assistance
• mental disorders; family
counseling, education, and
psychopharmacologic therapy.
• Transition planning at or by 12 years of age
17. Management, outcome, and
prevention
• The outcome; etiology, associated
conditions, the severity of the disability, and
environmental and social factors.
• mild ID; developmental velocity of one-half to
two-thirds of the rate of normal children
• moderate ID; one-third to one-half
• severe ID; one-quarter to one-third. Speech;
four to five years
• profound ID; < one-quarter ; life expectancy
varies with their mobility.
18. Management, outcome, and
prevention
•Primary prevention; preventing causative
conditions, alcohol and metabolic
diseases, neonatal screening programs.
•Secondary prevention; treating an
underlying condition, lead
toxicity, congenital hypothyroidism, and
metabolic diseases.
•Tertiary prevention; maximize function and
quality of
#Intellectual disability (ID) is a state of functioning that typically begins in childhood and is characterized by limitations in #intelligence and #adaptive skills #Naming revision from Mental Retardation to Intellectual disability brought DSM into alignment with terminology used by the World Health Organization’s International Classification of Diseases and organizations, such as the American Association on Intellectual and Developmental Disabilities.
Intellectual disability involves impairments of general mental abilities that impact adaptive functioning in three domains, or areas:• The conceptual domain includes skills in language, reading, writing, math, reasoning, and memory. • The social domain refers to interpersonal communication skills, the ability to make and retain friendships, and similar capacities. • The practical domain centers on self-management in areas such as personal care, and organizing school and work tasks.
#Intellectual disability (ID) is a state of functioning that typically begins in childhood and is characterized by limitations in #intelligence and #adaptive skills #Naming revision from Mental Retardation to Intellectual disability brought DSM into alignment with terminology used by the World Health Organization’s International Classification of Diseases and organizations, such as the American Association on Intellectual and Developmental Disabilities.
The severity of cognitive impairment is characterized by the extent of deviation of the IQ below 100, the estimated mean for the population. The lower limit of normal is considered to be two standard deviations below the mean or an IQ of70. The grade of severity include IQs in the following ranges:
#Global developmental delay — the terms intellectual disability (ID) or mental retardation usually are applied to children older than five years of age. Global developmental delay has been defined as performance at least two standard deviations below the mean in at least two of the following developmental subscales: #motor (gross/fine), speech and language, cognition, personal-social, and daily living skills
The causes of intellectual disability (ID) are extensive and include any disorder that interferes with brain development and functioning. Causes usually are classified according to the time of the insult, as prenatal, perinatal, and postnatal or acquired. In many cases, no etiology can be identified despite extensive evaluation. The proportion of cases of unknown cause is higher in mild ID. ID is more prevalent in developing countries or areas with lower socioeconomic status
Among the known prenatal causes of ID, the majority are genetic abnormalities. Genetic conditions are increasingly being diagnosed by technological advances, particularly chromosomal microarray testing. A genetic abnormality may have different and may present as ID alone or as ID associated with a clinical syndrome. Known genetic disorders or conditions include the following: Chromosomal abnormalities — Chromosomal aberrations as a group are the most common known cause of mental retardation [7]. Down syndrome, or Trisomy 21, is the single most common known genetic cause of ID, accounting for 9.2 percent of cases Anomalies of chromosome number and structure are the most frequent cause of unexplained, non-syndromic ID [15]. It is important to note, however, that copy number variants are not always pathological, and some copy number variants are part of normal variation.X-linked disorders — X-linked genetic disorders contribute in part to the increased prevalence of ID in males, accounting for approximately 16 percent of ID in males [18]. The most common is Fragile X syndrome which occurs in approximately 1 to 2 percent of individuals with ID and is one of the most common inherited disorders that cause developmental delay and IDAutosomal recessive disorders —Children of consanguineous parents have a 10 times increased risk of recessively inherited conditions including ID due to recessive variants they have inherited from a common ancestor [7,12]. Examples of mutations in autosomally inherited genes include PRSS12 (encodes a serine protease probably involved in neural synapses) [21], CRBN (involved in the regulation of mitochondrial metabolism) [22], CC2D1A [23], TUSC3 (involved in glycosylation) [24], GRIK2 (glutamate receptor 6) [25], and SYNGAP1 (involved in synapse function) [16].Autosomal dominant disorders — “De novo” (new) mutations in dominantly inherited genes are increasingly identified as an important cause of severe intellectual disability. Genetic conditions such as Mowat-Wilson syndrome (caused by mutation in the ZEB2 gene) or Pitt-Hopkins syndrome (mutation of the TCF4 gene) almost invariably arise as a result of “de novo” mutations.
Prenatal disorders also include a variety of other conditions. Of these, the leading cause is central nervous system (CNS) malformations. Other important prenatal causes of ID include congenital infection, and environmental toxins or teratogens (eg, alcohol, lead, mercury, hydantoin, valproate). Globally, prenatal exposure to alcohol is an important and potentially preventable cause of ID. Radiation exposure, especially between nine and 15 weeks gestation, is associated with ID. Congenital hypothyroidism that is unrecognized may cause cognitive delay.
Perinatal abnormalities that may lead to ID include preterm birth, hypoxia, infection, trauma, and intracranial hemorrhage. Some of these causes may have prenatal origins.
Postnatal and acquired causes of ID may be easier to identify, as they typically occur in an individual who was previously normal. Etiologies include accidental or nonaccidental trauma, CNS hemorrhage, hypoxia (eg, near-drowning), environmental toxins, psychosocial deprivation, malnutrition, intracranial infection, and CNS malignancy.
Children with ID usually are brought to the attention of a pediatrician because of parental concerns of language delay, immature behavior, immature self-help skills, or difficulty in learning. Parents may first recognize delayed development when a younger sibling overtakes an older child in these skills. A specific parental complaint of possible ID is unusual.Some children with mild ID may be undetected until school age. Most severely affected children are recognized before two years of age. Those who have a known genetic disorder may be diagnosed in infancy.gross motor skills in affected children are often less significantly delayed, except when neuromuscular abnormalities result in delay.Associated conditions; As the severity of ID increases, other conditions are more likely to be associated. Common problems that occur in children with severe or profound ID include mental disorders, including autism and other behavioral disorders, seizure disorders, motor handicaps affecting gross, fine, and speech motor functions, structural abnormalities, dysmorphism, and vision, hearing, and other sensory impairments. In some cases, these other morbidities are the presenting features, while in others they may be unrecognized. Comorbid endocrine abnormalities may also be present such as abnormal thyroid functions, short stature, and GH deficiency
The optimal order or timing of tests to identify the etiology of ID is not certain. The following assessments should be made in all children with ID •Complete history and physical examination•comprehensive developmental assessment•Complete vision and auditory screening•Review of newborn screening results•chromosomal microarray, CMA (also known as genomic microarray analysis) in all children with ID, unless a specific syndrome is suspected based on phenotypic characteristics and diagnosed by specific testing (table 2A). •If CMA is not available, then a G-banded karyotype is an appropriate substitute. Karyotyping is also preferred over CMA for patients with obvious chromosomal syndromes such as Down syndrome, a family history of chromosomal rearrangement, or a history of multiple miscarriages,
If there are Features requiring more comprehensive evaluation like parental consanguinity, prior unexplained infant death, multiple miscarriages, or loss or regression of developmental milestones, a comprehensive evaluation should be performed. In addition to the CMA or G banded karyotype the comprehensive evaluation should include a MRI, metabolic testing, and genetics consultation.
If the history or physical examination suggests Down, fragile X, or Rett syndrome or other genetic disorders, obtain specific tests for the disorder. •Obtain metabolic studies (concentrations of serum amino acids, urine organic acids, serum ammonia, and lactate) and thyroid screen (T4, TSH) if results are not available from newborn screening or if the history or clinical signs suggest a metabolic disorder or hypothyroidism. •The following disorders occasionally present with nonspecific findings and should be considered in children presenting with otherwise unexplained ID (see 'Metabolic testing' above):•Biotinidase deficiency: This disorder is included on the newborn screen in US states and is readily treatable. It may present with nonspecific developmental delay or with seizures, hypotonia, ataxia, and cutaneous abnormalities. •Duchenne muscular dystrophy: Screening for muscular dystrophy by testing creatinine kinase (CK) is valuable because some muscular dystrophies occasionally present with nonspecific developmental delay. •If the history of physical examination suggests CNS malformation or injury, obtain neuroimaging, preferably magnetic resonance imaging (MRI). •If the child has seizures or is suspected to have a syndrome that is associated with epilepsy, perform an electroencephalogram. •If risk factors are present for environmental exposure to lead, obtain a lead screen; testing for lead also should be considered in all mouthing, developmentally delayed children.
The overall goals of management of intellectual disability (ID) are to strengthen areas of reduced function and to minimize further cognitive deterioration. Interventions should begin early and be sustained. The approach should be collaborative and multidisciplinary. Depending on the individual’s needs, intervention may include speech and language therapy,physical therapy, family support, behavioral intervention, and educational assistance)Interventions for mental disorders that may be associated with ID include family counseling, education, and psychopharmacologic therapy. •Transition planning discussion should begin at or by 12 years of age
The outcome for ID is variable and depends upon the etiology, associated conditions, the severity of the disability, and environmental and social factors. (See 'Outcome' above.) •Children with mild ID typically have a developmental velocity of one-half to two-thirds of the rate of normal children, •Children with moderate ID typically develop at one-third to one-half of the expected rate•Children with severe ID develop at one-quarter to one-third of the expected rate. Speech development may be delayed until four to five years of age, or may never occur.•Children with profound ID develop at less than one-quarter of the expected rate. They need comprehensive assistance that is tailored to their physical needs. Their life expectancy varies with their mobility.
Primary prevention of ID is aimed at preventing causative conditions, such as prenatal exposure to alcohol and metabolic diseases detectable by neonatal screening programs. Secondary prevention of ID is directed at treating an underlying condition to reduce potential cognitive-adaptive dysfunction, such as treatment and surveillance for lead toxicity, congenital hypothyroidism, and metabolic diseases. Tertiary prevention refers to measures to maximize function and quality of life in an individual with ID.
