Learning Disability Flashcards
Outline the pathophysiology of Turners syndrome occur?
Inactivation of one of the X chromosomes in girls (all the genes unlike lyonisation)
Results in:
- Webbed neck
- Short stature
- Broad chest
- Gonadal dysfunction (amenorrhea and infertility) - ovarian failure pre-birth therefore puberty does not occur naturally
- Hypothyroidism
- Congenital cardiac abnormalities (1/3rd) - VSD or coarctation of the aorta
- Generally normal IQ - mean 90 - but may struggle with nonverbal communication, psychomotor and social skills
Only occurs in girls
What gene is affected in Lesch-Nyhan syndrome?
HPRT1 - affects the production of hypoxanthine-guanine phosphoribosyltranferase (HGPRT)
This recycles purine bases hypoxanthine and guanine - as they build up they get converted to uric acid
It is X-linked recessive - virtually all cases are males
Without HGPRT dopaminergic pathways get affected particularly mesotelencephalic:
- substantia nigra to putamen –> dystonic motor ability
- Ventral Tegmentum to PFC and Nucleus Accumbens –> peculiar behaviour
Outline some features of Lesch Nyhan syndrome?
Build up of uric acid:
- Hyperuricaemia
- Gouty tophi/arthritis
- Nephrolithiasis
IQ 60 - 70
Attentional difficulties - relatively preserved language and verbal ability
Self injurious behaviour - extinction at time of behaviour and restraints
Dystonia superimposed on hypotonia, usually cannot walk and wheelchair bound. May have choreoathetosis or corticospinal signs
Loss or abnormality of psychological, physiological or anatomical structure or function is….
Impairment - refers to bodily structure and function
Outline the genetics of Down’s syndrome?
Full trisomy 21 - not inherited - 95% of cases - nondisjunction 88% from Mum / 12% from Dad
Translocation - inherited - 2-3% of cases - balanced translocation
Mosaicism - not inherited - 2-3% of cases - occurs during fetal development at a random time point
Classify intellectual disability according to IQs
Mild 50 - 70 (85%) - most lead normal lives
Moderate 35-49 (10%) - use simple language when talking, understand speech better, may be able to learn simple ADLs more complex requires support and supervision.
Severe 20 - 34 (3 - 4%) - may live independently with supervision
Profound < 20 (1 - 2%)
Name some drugs known to cause dysphagia in LD
Clonazepam
Haloperidol
Metoclopramide
Phenothiazines
Name some appropriate screening tools for dementia in LD?
DLD
DSDS - dementia scale for downs syndrome
Name some risk factors for self-harm in those with LD?
Younger age
Lower developmental ability
Autistic symptoms
Sensory impairment
What is the most common symptom of PTSD in those with learning diability?
Aggression
Disruptive/defiant behaviour
Others:
Self-harm
Agitation/jumpiness
Distractibility
Sleep problems
Depressed mood
Is Schizophrenia reliably diagnosed in individuals with an IQ < 45
No psychosis NOS is used
Are stimulant drugs as effective in individuals with LD?
May be less effective
Additionally could precipitate tics in those with tourette’s or ASD
Are people with LD more or less likely to experience adjustment disorder?
Seems more likely - more sensitive to loss of loved ones / changing roles
What is the co-morbid prevalence of the following conditions with LD?
Problem behaviour
Autism
Affective Disorder
Schizophrenia
OCD
ADHD
Personality Disorder
Psychotic Disorder
Anxiety Disorder
Problem behaviour - 22.5%
Autism - 7.5%
Affective Disorder - 6%
Schizophrenia - 3%
OCD - 0.7%
ADHD - 1.5%
Personality Disorder - 1%
Psychotic Disorder - 4%
Anxiety Disorder - 4%
Name some signs of dyslexia?
- Confusing the order of letters in words
- Poor or inconsistent spelling
- Understand information when told verbally, but have difficulty with information that’s written down
- Put letters the wrong way round (such as writing ‘b’ instead of ‘d’)
- Pronouncing long words incorrectly and ‘jumbling’ up phrases (for example, saying ‘hecilopter’ instead of ‘helicopter’, or ‘beddy tear’ instead of ‘teddy bear’)
- Poor handwriting
What factors may contribute to the development of learning disability?
Genetic factors
- i.e. Downs syndrome
- Deletions and duplications
- X-linked recessive and dominant conditions
- Mitochondrial and metabolic disorders
- Presumed polygenetic conditions like neural tube deficits
External prenatal factors
- Infections - rubella, CMV, syphillis, toxoplasmosis, HSV and HIV
- Toxins e.g. alcohol, drugs and opioids
- Maternal illness - diabetes, hypertension, hypothyroidism etc
Perinatal factors
- Premature infants and low birth weight
- Infections e.g. meningitis, encephalitis, neonatal septicaemia
- Birth asphyxia and intracranial haemorrhage
- Newborn complications - respiratory distress or hyperbilirubinaemia, hypoglycaemia
Postnatal factors:
- CNS infections, intracranial tumours
- Hypoxic brain injury
- Head injury
- Exposure to toxins
- Psychosocial environment
What is social role valorisation?
SRV in LD is the idea of including and creating roles for people with LD in society would allow these individuals to be valued differently - expanded to include concepts of respect, opportunity, development of competence, individual living and individual choice
Name a useful screening tool to assess for psychiatric symptoms in individuals with LD?
PAS - DD
Psychiatric assessment schedule for adults with developmental disability
- Available as a checklist for staff to decide who may need more detailed assessment and mini version without interview
What specific LD syndrome’s occur with psychosis?
Usher’s syndrome - retinitis pigmentosa, congenital deafness, vestibulo-cochlear ataxia, LD in 23% and psychosis in 15%
Velo-cardio-facial syndrome
Prader Willi - association with psychosis
Name some phenotypic features of downs syndrome?
- General hypotonia
- Oblique/upslanting palpébral fissures
- Small flattened skull
- High cheekbones
- Protruding tongue
- Short stature
- Overweight
- Wie nasal bridge
- Brushfield spots - grey or very light yellow spots on iris
- Epicanthic fold
- Low set ears
- SIngle plmar rease
- Syndactyly
- Short broad hands
Congenital features:
- VSD
- Mirtral valve disease
- Patent ductus arteriosus
- GI abnormalities
- Hirschsprung disease
- Umbilical and inguinal hernia
What is the genetics of fragile X and name some features
Trinucleotide repeat (CGG) on X - on FMR1 gene Xq27.3
> 200 repeats considered pathological
More common in men > women
Elongated face, large ears, short stature, large testicles, hyper-extendible joints
Association with epilepsy and ASD (may behave similar too with shyness, poor eye contact, conversational rigidity)
Men affected have moderate/severe LD, women may only have mild LD (IQ tends to be dip pre-adolescent then stabilises with increases in adaptive functioning after this)
Accounts for 10-12% of LD in men
Men affected more than women
How do Prader Willi and Angelman syndromes differ genetically and phenotypically?
PWS - 15q11 deletion - inherited from father:
- Hyperphagia
- Skin picking
- Obesity and striate
- Mild LD
- Small gonads, incomplete sexual development
- Hypotonia and delayed motor development
- Almond shpaed eyes, flat face, thin upper lip
Angelman syndrome:
- Happy disposition, paroxysmal laughter, hand flapping, clapping, ataxia T
- Severe/profound LD - with pronounced verbal delay
- Fair hair and blue eyes, microcephaly with a flat occiput (short and broad skull)
- Long face, prominent jaw and wide spaced teeth
- 90& have epilepsy
The genetics of Williams syndrome is?
Deletion of 7q11
Features:
- Elfin like face
- Disinhibited socially and with strangers or anxious and fearful
- Advanced verbal skills but speech is superficial (cocktail party speech) (Verbal skills > visuospatial and motor) (typically mild - moderate LD)
- Supravalvular stenosis
- Sensitive hearing
- Hypercalcaemia
- Thyroid problems
- Renal problems
How does Cri-du-chat present?
Results from deletion on 5p
Symptoms:
- Cat like cry
- Hypotonia
- Microcephaly
- Hypertelorism (increase in space between two body parts)
- Down turned mouth
- Severe to profound LD
- Epicanthal folds - parallel to nose
- Slanting palpebral fissures
- Miceognathia
- Hyperactive, stereotypes and self-injury
- Congenital heart disease and GI abnormalities
Smith-Magnesis Syndrome presents with?
Pronounced self-injurious behaviour
Self-hugging
Hoarse voice
Mild/moderate LD (75%)
Sleep disturbance (decreased or absent REM)
Results from deletion (complete or partial of 17p11.2 (cognitive impairment correlates with the size of deletion)
How does Edwards syndrome present?
Die soon after birth
Rocker bottom feet
Webbing of second and third toes
Severe LD
From Trisomy 18
How does Patau syndrome present?
Severe intellectual disability
Babies often die soon after birth.
Most have congenital heart malformations, anophthalmia and a cleft palate.
Other common features include polydactyl, microcephaly, and overlapping of fingers over thumb
How does tuberous sclerosis present as?
Hamartomatous tumours affecting various organs including brain, kidney and heart tissue
ADHD
ASD
Epilepsy is common
LD of all degrees
Depigmented skin patches (Ash Leaf Spots)
Fibromas of nails
Implicates to affect 16p and 9q - autosomal dominant
Type 1 and type. 2 exist
How does Rubenstein Tabi present?
Short
Small heads
Friendly disposition
Moderate - severe LD
Propensity for self-stimulatory activities
Beaked nose
Short eye lashes
Broad thumbs and great toes
Thin upper lip
Differentiate Aspergers from ASD?
No overt language delay or global cognitive impairment that can occur
Aspergers may have specifics difficulties non-verbal communication or executive functioning
How does Rett syndrome present?
Almost exclusively females
Initial normal development (6 - 18 months) then regression:
- Loss of all acquired language skills
- Characteristic hand flapping movements
- Ataxia
- Psychomotor retardation
- Deceleration in head circumference resulting in micropcepahly
- Epilepsy and seizures with EEG abnormalities
- Breathing problems (hyperventilation, apnoea, and breath holding)
- Daytime somnolence
Often grow up to be wheelchair bound with no verbal ability
Xq28
What is the incidence of Downs in women aged
a) < 25
b) 25 - 30
c) 30 - 35
d) 35 - 40
e) > 45
a) 0.5/1000
b) 0.7/1000
c) 5/1000
d) 25/1000
e) 36/1000
What is a monosomy?
Only having one chromosome
Name some features of foetal alcohol syndrome?
Microcephaly
Short palpebral fissures
Flat philtrum
Thin upper lip
Short stature
Small maxillae and mandibles
Mild - moderate LD
Irritability / inattention / memory problems
Are people with Kleinfelters taller or smaller on average?
Smaller
How is fragile X transmitted?
X-linked dominant
Females shower lower penetrance due to the protective effects of the second X chromosome
How is Hunter’s syndrome inherited?
X - linked recessive - leads to an accumulation of Glycosaminoglycans
Which LDs is epilepsy most common in?
Angelman syndrome, Rett Syndrome and Tuberous Sclerosis (90% for these conditions)
Down’s 5-10%
Fragile X 20-25%
How is PKU transmitted?
Autosomal recessive
Prescribing Lithium to those with LD what investigation should be done?
EEG - due to Lithiums ability to lower seizure threshold and the prevalence of epilepsy in those with LD
