Fragile X Flashcards
What gene is affected in Fragile X Syndrome?
FMR1
Fragile X Mental Retardation 1 gene
How is Fragile X inherited?
X linked
What two factors cause disease in Fragile X?
- Unstable CGG trinucleotide repeat >200 (normal 5-40)
2. Hypermethylation of FMR1= gene silencing and decreased production of FMR1 protein (most imp predictor severity)
How many CGG repeats cause premutation in Fragile X syndrome?
55-200
Name three manifestations of premutations in Fragile X
- Mild cognitive delay
- Behavioural deficits
- Primary ovarian insufficiency (20% women)
- Fragile X associated ataxia/tremour in majority of older men
Name 3 facial features of Fragile X Syndrome.
- Prominent forehead
- Long narrow face
- Prominent jaw
- Protuberant ears
Name 1 GU manifestation of Fragile X
- Macro-orchidism (50mL, 80% by age 9)
OR - Inguinal hernia 1-3yo
Name 2 ENT features of Fragile X
- High arched palate
2. chronic otitis media
Name 2 cognitive affects of Fragile X
- Moderate to severe intellectual disability (IQ 40)
2. Language delay
Name 2 behavioural manifestations of Fragile X
- ADHD
- Autism (30%)
Agression, self injury, emotional lability, good sense of humour
Name 2 MSK features Fragile X
- Connective tissue dysplasia (soft velvety skin)
- Joint hypermobility
pes planus, scoliosis, clubfoot
Name 2 eye features of Fragile X
- Strabismus
- Refractive errors
ptosis, nystagmus
What cardiac feature should you watch out for in Fragile X
MVP
What are 2 neuro features of Fragile X?
- seizures
- hypotonia as a neonate
macrocephaly
Who should be tested for Fragile X (4 conditions)
- Children with developmental delay
- Children with borderline intellectual abilities
- Children with intellectual disability
- Children with autism
