Intellectual Disability Flashcards
(43 cards)
ICD 11 INTELLECTUAL DISABILITY DEFFINITION
A group of etiologically diverse conditions
originating during the developmental period
significantly below average intellectual functioning and adaptive behaviour
[approximately two or more standard
deviations below the mean
Intellctual Disability Levels and freguency
Mild: IQ 50-69, adult mental age 9-12 y 85%
Moderate: IQ 35-49, adult mental age 6-9 y 10%
Severe: IQ 20-34, adult mental age 3-6 y 4%
Profound: IQ under 20, adult mental age under 3 y 1%
Differential Diagnosis of ID
Sensory and communication problems
Environmental neglect
ASD
Severe ADHD (especially inattentive type)
Schizophrenia
Other psychopathology
Predisposing factors ( definite etiological connection)
1) genetic differences (including inborn errors of metabolism
[IEM]), accounting for 30%–50% of cases;
2)environmental influences and
exposure to toxins during prenatal development (e.g., fetal alcohol
syndrome), which affect 10% of cases;
3) pregnancy and perinatal
complications (e.g., trauma, prematurity, hypoxia), affecting 10% of cases;
4) acquired medical conditions (e.g., lead poisoning), affecting 5% of cases
Risk factors ( probably related to unknown cause)
mothers older than 35 years, Black mothers,
lower level of maternal education,
three or more births,
maternal alcohol use,
maternal epilepsy,
preterm birth,
male sex
low birth weight.
Most influential risk factors of idiopathic ID
I. low birth weight
II .maternal epilepsy
III. preterm birth.
Other significant, but weaker: maternal tobacco use, diabetes,
hypertension, and asthma.
Study on antipsychotics for agressive behaviour in ID
Tyrer et al, 2008:
Compared flexible doses of haloperidol, risperidone
and placebo, in 86 non-psychotic patients . randomly assigned to haloperidol (n=28), risperidone
(n=29), or placebo (n=29). Placebo group showed the greatest change
Congenital Syndromes and Neurobehavioral
Phenotypes in ID
Deletion Syndromes
Uniparental Disomy
Aneuploiies
X- linked syndromes
Chemotaxis Syndromes
Fetal Alcohol spectrum disorders
Inborn errors of metabolism
What is the prevalence of 16p11.2 deletion syndrome?
1 per 3,000–5,000
It accounts for approximately 0.4% of ID cases.
What are common comorbidities associated with 16p11.2 deletion syndrome?
- Mild ID
- Psychiatric disorders
- Developmental disorders
- Expressive language deficits
- Speech apraxia
What percentage of children with 16p11.2 deletion syndrome are diagnosed with ASD?
20%
What is the most frequent chromosomal microdeletion syndrome in humans?
22q11.2 deletion syndrome
What is the estimated prevalence of 22q11.2 deletion syndrome?
1:2,000–4,000
Di Georgi Syndrome mnemonic
C: congenital heart disease (particularly conotruncal anomalies)
A: abnormal facies (hypertelorism, low set ears, short philtrum, among others)
T: thymic hypoplasia
C: cleft palate/cellular immune deficiency
H: hypoparathyroidism with hypocalcaemia
22: deletion located on chromosome 22
What cognitive impairments are associated with 22q11.2 deletion syndrome?
- Cognitive control difficulties
- Attention issues
- Social cognition deficits
What is the prevalence of Williams syndrome (WS)?
1 per 7,500
What are characteristic features of Williams syndrome?
- Elfin appearance
- Stellate iris
- Connective tissue abnormalities
- Cardiac abnormalities
- Growth deficiency
What cognitive profile is typical for individuals with Williams syndrome?
Mild to moderate ID and learning disorders
What is the prevalence of Angelman syndrome (AS)?
1 per 12,000–20,000
What genetic causes underlie Angelman syndrome?
- Deletion of maternally inherited chromosome 15q11.2–q13
- Uniparental disomy of paternal chromosome 15
What is a distinctive neurocognitive profile of Angelman syndrome?
- Severe speech impairment
- Inattention
- Gait ataxia
- Inappropriate laughter
What is the estimated prevalence of Prader-Willi syndrome (PWS)?
1 per 10,000–30,000 births
What are common features of Prader-Willi syndrome?
- Hypotonia
- Global developmental delay
- Hyperphagia
- Obesity
What is the most common genetic cause of intellectual disability?
Down syndrome (DS)
