Common symptoms of childhood include:
• Global developmental delay / intellectual disability
• Spoken language reduced to absent; comprehension is usually better
• Low muscle tone (floppy)
• Seizures, common to have multiple types
• Disordered sleep, usually frequent waking during the night
• Repetitive behaviours and movements
• Vision changes that often require correction with glasses
Common symptoms in adulthood include:
• Cognitive decline / dementia
• Parkinsonism (tremors, slow movement, balance problems, rigid muscles)
• Dystonia (muscle cramping/writhing), spasticity (tight muscles)