What Are the Specific Symptoms of Fragile X Syndrome?

Fragile X syndrome symptoms include impaired language ability, short-term memory, and problem-solving skills.

Fragile X syndrome (also called Martin-Bell syndrome or marker X syndrome) is the most common cause of intellectual disability and autism, and is the second most common cause of genetically associated mental deficiencies, after Trisomy 21.

Symptoms of fragile X syndrome include:

• Developmental
  • Delated milestones in infancy
  • After the first year, delays in speech and language and fine motor skills
  • Repetitive vocalizations
  • Impaired language ability, short-term memory, and problem-solving skills
• Cognitive
  • IQ often in the range of 20-70 indicating mild-to-severe mental retardation 
• Neuropsychological
  • Depression
  • Anxiety
  • Oppositional defiant disorder – uncooperative, defiant, hostile behaviors
  • Autistic-like behaviors
  • Attention deficit-hyperactivity disorder (ADHD) behaviors in males including aggression
  • Seizure disorders 
  • Problems with changes in routines, especially in children
  • Characteristics of obsessive-compulsive disorder (OCD), and/or sensory integration disorder
  • Self-injurious behavior and temper tantrums
• Musculoskeletal
  • Flat feet (pes planus)
  • Chest wall disorder (pectus excavatum)
  • Joint laxity
  • Scoliosis
  • Joint dislocation
• Feeding difficulties
  • Acid reflux
  • Vomiting
  • Failure to gain weight during infancy and childhood (rare)
  • Prader-Willi phenotype 
• Toilet training problems
• Sleep disturbances
  • Difficulty falling asleep (insomnia)
  • Frequent awakening
  • Loud snoring, with or without obstructive sleep apnea
• Recurrent medical conditions
  • Recurrent sinus infection (sinusitis)
  • Ear infections (otitis media)
  • Decreased visual clarity

Fragile X syndrome is caused by a genetic mutation. It is passed on the “X” chromosome. Women have two “X” chromosomes (XX), and men have one (XY). Fragile X is more common in males than in females, because if a female receives a damaged X chromosome from her mother, she may still inherit a healthy X chromosome from her father and thus not develop the syndrome. 

A woman who carries the fragile X mutation has a 50% chance of passing the mutated gene to her children. The children will either be carriers or they will have fragile X syndrome.

Men who are carriers pass the mutation to daughters but not sons. The daughters are carriers but they do not have fragile X syndrome.

Fragile X syndrome is diagnosed using DNA testing. Testing may be done on children or adults suspected of having the condition and people who have family members with the condition to see if they carry the gene. Pregnant women may also test their unborn baby for the genetic mutation if the condition runs in the family. 

Children who are diagnosed with fragile X syndrome will need further tests. These include tests to check their thinking, learning, and behavior.

Treatment for fragile X syndrome involves management of the medical problems caused by the condition. 

Treatment usually involves:

Regular doctor visits to monitor the child for problems

• A learning plan for school for children
• Behavioral therapy 
  • May include social eye contact and stress reduction training
  • Skills-oriented therapy
  • Individual counseling 
• Speech, language, physical, or occupational therapy to help with everyday activities
• Medications
  • ADHD medicines such as stimulants
  • Antidepressants such as serotonin reuptake inhibitors (SSRIs)
  • Anti-anxiety medications
  • Anti-seizure medications
  • Antipsychotic agents for irritability, aggression, mood instability, and perseverate behaviors
• Special diet
  • For patients with gastroesophageal reflux disease (GERD)
  • For patients with the Prader-Willi syndrome phenotype
• Genetic counseling for families 
• Treatment for lazy eye due to strabismus (misalignment of the eyes) 
• Treatment for chronic sinus infections (sinusitis) and chronic ear infections (otitis media)
• Orthotic inserts or orthopedic shoes for flat feet (pen planus)
• Surgery for severe scoliosis

Complications of fragile X syndrome in include: 

• Seizures
• Chronic ear infections
• Heart valve abnormalities such as mitral valve prolapse 
• Lazy eye caused by misalignment of the eyes (strabismus)
• Joint problems and flat feet
• Scoliosis
• Depression 

Fragile X syndrome may cause many different health problems; however, life expectancy is typically not affected by the disorder.