Transcript Fragile X

Care of People with
Learning Disabilities
Dr James K. Betteridge
September 2011
Outline
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Introduction – Definition and Prevalence
Case
Classification
Assessment
Management
Examples
– Down’s Syndrome
– Fragile X
Key Messages…RCGP
• In managing patients with learning
disabilities, GPs should:
– Be aware of likely associated conditions and
know where to obtain specialist advice
– Understand how psychiatric and physical
illness may present atypically in patients with
LD who have sensory, communication and
cognitive difficulties
– Use additional skills of diagnosis and
examination in patients unable to describe
symptoms
Prevalence
DIAGNOSIS
Per GP List of 2000
Down’s Syndrome
2
Fragile X
1
Cerebral Palsy
1
Autism Spectrum Disorder
1
Misc.
3
• 2.5 x associated medical problems
• 3 x number of repeat prescription drugs
prescribed by primary care
• Major economic burden on NHS, Social
Services and social security system
Definitions
• WHO defines learning disabilities as: “a state of
arrested or incomplete development of mind.”
• It is a diagnosis but is not a physical or mental
illness.
• Three criteria are required before learning
disabilities can be identified:
– Intellectual impairment
– Social or adaptive dysfunction (Poor Life Skills)
– Early Onset – birth/ early childhood
• Epidemiology – 1.5% of population
Case Illustration:
Home Visit
Assessing Intellect
Intelligent Quotient
(IQ)
• Standardized tests in
different domains of
intelligence
– Median score is set at
100 with a standard
deviation of 15
– This means 68% of
population should
have an IQ between
85 and 115
MENSA
• Derivation “mens” Latin for Mind, “mensa”
Latin for Table
• A round-table society of minds
• Need IQ above 98th percentile to join – i.e.
IQ above 145.
LD Classification
• Mild (IQ 50-70) – 80%
– Not usually associated with abnormalities in
appearance or behaviour
– Language, sensory, motor abnormalities are
mild or absent
– Problems not apparent until school age
– Difficulty coping with stress or more complex
areas of social functioning e.g. parenting,
financial management.
– Usually live independently, engage in
employment
LD Classification
• Moderate (IQ 35-49) 12%
– Limited language
• Severe (IQ 20-34) and Profound (>20) 8%
– Very limited communication and self-care skills
– Associated physical disabilities
• Epilepsy 33%
• Inability to walk 15%
• Incontinence 10%
– May use non-verbal communication e.g.
pointing, signing (Makaton)
Aetiology
•
Mild LD
– No specific cause
– Bottom end of normal
distribution curve
– Considerable genetic
contribution
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Correlation between low
parental and low childhood IQ
due to social and educational
deprivation.
Aetiology
• More severe LD
– Usually related to specific brain damage
• Antenatal
– Genetic, Infective, Hypoxic, Related to maternal disease
• Perinatal
– Prematurity, Birth hypoxia, Intracerebral bleed
• Postnatal
– Infection, Injury (?NAI), malnutrition, hormonal,
metabolic, toxic, epileptic
Genetic Causes of LD
• Chromosomal
– Down’s (Trisomy 21)
– Klinefelter’s (XXY), Turner’s (X0), Fragile X
• Autosmal Dominant
– Tuberose sclerosis, neurofibromatosis
• Autosmal recessive
– Usually associated with a specific metabolic
condition e.g. Phenylketonuria
Down Syndrome
Down Syndrome
• Commonest specific cause of LD
• LD usually moderate or severe but mild in
15%
• Chromosomal condition caused by the
presence of all or part of an extra 21st
Chromosome
• Named after Dr John Langdon Down 1866
• 1 in 733 births
• More common in older parents due to
increased mutagenic effects on reproductive
organs
D.S – Clinical Features
Learning disability
• Language
– (Language delay – difference between
understanding and expressing speech)
– Common to screen for hearing
• Motor skills
– Fine motor skills lag behind – can interfere
with cognitive development
– Gross motor skills vary – Walking age 2-4
• May benefit from physiotherapy to enhance
D.S. – Clinical Features
Screening for DS
• Pregnant women in the UK are offered screening
for Down Syndrome
• Combined Test:
– 85% detection rate, 5% False Positive
– Ultrasound Scan (8-14/30 or first dating scan)
• Nuchal translucency (fat pad behind neck)
– Blood Test
• Looks at Free Beta HCG and PAPPA (Pregnancy Associated
Plasma Protein A
• 2002 – Abortion rate of c. 92%
D.S. – Later Life
• Life expectancy 49 (2002)
• People with DS surviving
beyond the age of 50
invariably develop
neuropathological changes
akin to Alzheimer’s disease
visible on post mortem
• At least 50% have clinical
dementia
Fragile X
• Second most common cause of LD
• 1 in 36000 male and 1 in 5000 female
births
• Accounts for 8% of males with LD
• Caused by expansion of a single
trinucleotide gene sequence (CGG)on the
X chromosome
• Results in failure to express the protein
coded by the FMR1 gene, which is
required for normal neural development
Fragile X
Fragile X – Physical Features
• Large Head
• Large Ears
• Connective Tissue
Disorders
• Low Muscle Tone
• Flat Feet
• Macro-orchidism
• High arched palate
• Mitral Valve Prolapse
Fragile X – Psychiatric Features
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Abnormal speech
Impulsivity and hyperactivity
Hand-biting, hand flapping
Poor eye contact
Unusual responses to sensory stimuli
4% have autistic features
Women often have less severe behavioural
problems and only 1/3 have significant LD
– WHY? Think genetics…..
LD and Psychiatric Illness
• Making diagnoses difficult due to coexisting
language deficits
• Behavioural disturbance common :
– Self-injurious, aggressive, inappropriate sexual
• Schizophrenia has prevalence of 3% in LD
– Simple, repetitive hallucinations
• Depression and anxiety disorders higher
than general population
Management of LD (1)
• Most people with LD live with their families
• Support from primary care, educational and
social services
• MILD
– Children - mainstream school with support
– Adult – support to work in mainstream jobs
• Small minority with Severe/Profound and usually
behavioural problems require residential care
• MDT approach to coordinate services –
specialist psychiatric services
– Mental illness, Physical illness, Finances, Housing
Management of LD (2)
• Need for accessible information for patients
• May face distress at realisation:
– They many not achieve full independence
– Their parents are likely to die before they do
– Issues surrounding sexuality
• Sensitive but frank communication at a level the
patient can understand is important
• REMEMBER – people with LD, especially those
living in institutions are at increased risk of
physical, emotional and sexual abuse.