Genetics - Fragile X Syndrome

Question 1

What is Fragile X syndrome?

Answer 1

Mutation in FMR1 (fragile X mental retardation 1) gene on X chromosome

FMR1 gene codes for fragile X mental retardation protein, which helps cognitive development

Question 2

How is Fragile X syndrome inherited?

Answer 2

X-linked, not clear if dominant or recessive

Males always affected, females can vary in how much they’re affected

Females have non-mutated FMR1 gene on other x chromosome, so can vary in how affected

Can also have de novo mutation

Question 3

What are the features of fragile X syndrome?

Answer 3

Delay in speech and language development

• Intellectual disability
• Long, narrow face
• Large ears
• Large testicles after puberty
• Hypermobile joints
• ADHD
• Autism
• Seizures

Question 4

How is fragile X managed?

Answer 4

Supportive and involves treating symptoms

MDT management for learning disabilities

Question 5

What is life expectancy like in fragile X?

Answer 5

Similar to general population

Depends on associated disabilities and complications