Fragile X Syndrome is a X-linked dominant genetic mutation resulting in multiple facial abnormalities and intellectual disability. It is diagnosed with genetic testing and treated with supportive care.

Pathophysiology

• FMR1 gene mutation - unstable triple repeat expansion
• X-linked dominant

Contextual Factors

• Most common inherited cause of intellectual disability
• More commonly affects males

Clinical Manifestation

Physical

• Large, protuberant ears
• Prominent chin
• Prominent forehead
• High-arched palate
• Macroorchidism (post-pubertal)
• Hyperextensible joints
• Mitral valve prolapse

Cognitive

• Mild to moderate intellectual disability
• Autistic features

Premutation Features

• Premature ovarian failure - mid-30s menopause
• Fragile X-associated tremour/ ataxia syndrome (FXTAS)
  • Gait abnormalities
  • Intention tremours
  • Later intellectual impairment

Complications

• Connective tissue disorders

Diagnosis

• DNA testing
  • CGG repeats

Treatment

• Supportive care
• Early intervention for autism symptoms
• Psychiatric medications