Fragile X Syndrome

Question 1

Information

Answer 1

1/4000 males
1/6000 females - less severe as have protective (second) X chromosome

impaired cognitive ability

Caused by expansion of the CGG repeat at beginning of FMR-1 (fragile X mental retardation - 1) gene on X chromosome

most common form of intellectual disability

typically diagnosed at 3-4 years

Question 2

Brain differences

Answer 2

Hoeft et al (2010) - grey and white matter brain differences

• 1-3 yo boys
• enlarged GMV (grey matter volume) caudate (learning), thalamus (sensory processing) and fusiform gyri (recognition)
• reduced GMV in cerebellar vermis (movement)
• enlarged WMV in striatal-prefrontal regions (adolescent development)
• early (possibly prenatal) genetically mediated alterations in neurodevelopment

Question 3

Hoeft et al (2010)

Answer 3

MRI scans looking at differences between brain areas (grey and white matter comparison)

Question 4

What causes FXS

Answer 4

expansion of the CGG repeat at beginning of FMR-1 gene on chromosome X

• Individuals are classified as having a full mutation (200–2,000 repeats), pre mutation (50–200 repeats), or normal (5 –50 repeats) allele based on the size of the CGG expanded region

Question 5

Physical features

Answer 5

long and narrow face
prominent jaw and ears
flat feat

Question 6

Cognitive and behavioural profile (M)

Answer 6

Males

• IQ = 40
• communication impairment (language and social)
• hyperactivity
• inattention
• impulsiveness
• hyper arousal
• delayed motor development

Question 7

Cognitive and behavioural profile (F)

Answer 7

Females

• IQ = 70
• social difficulties (emotional, anxiety and depression)

Question 8

Strengths of individuals

Answer 8

• imitation
• good visual learners
• personable (sense of humour and sensitive)

Question 9

First signs

Answer 9

• sensory and motor atypicality (9-12m)
• decreased object play
• leg stereopsis
• atypical posture
• prolonged visual attention
• missing milestones can alert parents to seek medical attention (most disorders)

Question 10

common features

Answer 10

> short attention span
distractibility
impulsiveness
restlessness

• overacting sensory problems
• social difficulties (anxious)
• emotional difficulties
• communication difficulties

> = ADHD
- = Autistic

Question 11

comorbidity

Answer 11

• with ADHD and Autism
• dual diagnosis of autism (50-90% symptoms, 25-80% diagnosed)
• poor eye contact
• hand flapping
• ADHD symptoms prevalence (54-59%)
• epilepsy also common

Question 12

dual diagnosis of autism

Answer 12

symptoms = 50-90%
diagnosed = 25-80%

Question 13

comorbidity with ADHD

Answer 13

symptom prevalence = 54-59%

Question 14

adaptive behaviour

Answer 14

• everyday skills or tasks that a person can do
• measured via the Vineland adaptive behaviour scale (standardised)
• assesses real life skill and independence
• semi structured parent interview to identify whether there are areas to help develop within a child
  (communication, daily living, socialisation, motor skills)
• need to consider child developmental trajectory (Annette Karmiloff-Smith)
• positive environmental influences may act as protective factors (Glaser et al., 2003)

Question 15

Glaser et al., 2003 - POPE

Answer 15

suggested that parental expectation, parental skill, emotional climate and organisation of the home are all influential factors

• IQ was the strongest predictor of outcomes

Question 16

Annette Karmiloff-Smith

Answer 16

need to consider child developmental trajectory

- it is important to consider early predictors of risk and experience