Fragile X Syndrome (FMR1) DNA Analysis with Reflex Test

  • Fragile X syndrome is an inherited developmental disorder characterized by intellectual and behavioral disabilities
  • Defects in the FMR1 gene cause Fragile X Syndrome
  • It is the most common inherited form of mental impairment, affecting 1 in 4000 boys and 1 in 8000 girls
  • Simple mouth swab DNA test with results in 1 – 2 weeks
Order Test Kit

What is Fragile X Syndrome (FMR1) DNA Analysis?

The FMR1 gene (fragile X mental retardation 1) encodes FMRP (fragile X mental retardation protein). FMRP is involved in cognitive development and female reproductive functions. Individuals with fragile X syndrome have genetic changes in FMR1 and do not make enough FMRP. FMR1 is located on the X chromosome and only one defective copy of FMR1 is necessary to cause the disease. The genetic changes in the FMR1 gene can be broadly categorized into three groups:

  • Intermediate – These individuals have only mild or borderline forms of the FMR1 mutations and are unlikely to show any symptoms.
  • Premutation – These individuals are known as carriers. They do not have fragile X syndrome but have an increased risk for psychiatric disorders and other fragile X-associated symptoms.
  • Full Mutation – These individuals are affected by the symptoms of fragile X syndrome, including intellectual disabilities and typical physical characteristics.


Order Test Kit


The kit can be ordered online, by fax or mail, or by phone. Once you place the order, the testing kit will be shipped directly to you. The kit contains swabs called “buccal swabs”. DNA is collected quickly and easily by rubbing the swabs inside your mouth against the cheek for 30 seconds. Once the DNA is collected, the swabs are placed into the specimen container provided in the kit and returned to the laboratory for testing using the return package included in the testing kit. Once your samples arrive at the laboratory, testing begins immediately and results are available in 1 to 2 weeks.

Order Test Kit

Types of Fragile X-Associated Disorders

Fragile X Syndrome (FXS)

Fragile X syndrome, also known as the Martin-Bell syndrome, is a common form of inherited mental impairment. Individuals with fragile X have a normal life expectancy, but will need extra support and care most of their lives. Symptoms are often more severe in men. Fragile X is characterized by:

  • Altered or arrested development
  • Decreased intelligence and learning ability (low IQ)
  • Speech and language disabilities
  • Emotional issues such as anxiety
  • Sensitive to certain stimuli
  • Hyper-extensible finger joints
  • Large testis after puberty
  • Large head
  • Long face
  • Prominent forehead and chin
  • Protruding ears

Fragile X-associated Tremor Ataxia Syndrome (FXTAS)

Fragile X-associated tremor ataxia syndrome is a neurodegenerative condition that can develop later in life in carriers of the fragile X premutation. Approximately 1 in 260 women and 1 in 800 men are carriers of the fragile X permutation. 33% of male carriers of the premutation and 10% of female carriers of the permutation are affected by FXTAS. FXTAS is often misdiagnosed as other neurological conditions such as Parkinson’s disease, Alzheimer’s disease, or dementia. Symptoms of FXTAS include:

  • Symptoms that appear between the ages of 50-80
  • Progressively more severe action tremor
  • Balance problems that cause falling or instability when walking
  • General shaking of body parts
  • Numbness in extremities
  • Delusions
  • Mood instability
  • Irritability
  • Changes in personality
  • Short-term memory loss
  • Gradual intellectual decline
  • Difficulty learning new tasks
  • Loss of function skills such as organizing, planning etc.
  • Orthostatic hypotension
  • Thyroid disorders (specific to women)
  • Seizures
  • Fibromyalgia and general muscle pain (specific to women)

Fragile X-associated Primary Ovarian Insufficiency (FXPOI)

Fragile X-associated primary ovarian insufficiency (FXPOI) is a condition in women who are carriers of the fragile X premutation where the ovaries do not function at full capacity. All women with the premutation experience decreased fertility, however, only 20-28% of carriers will develop FXPOI. While these women are able to conceive, they are at higher risk of having children with fragile X syndrome. Symptoms of FXPOI include:

  • Early menopause before the age of 40
  • Decreased fertility
  • Irregular menstrual cycles
  • Low estrogen levels
  • High levels of the FSH hormone

Frequently Asked Questions

Avada Admin

The Disease

If my parents or grandparents have fragile X syndrome, am I at increased risk? How common is fragile X syndrome? What are the symptoms of fragile X syndrome?

Learn More
Avada Admin

The Test

What is the FMR1 gene? What changes in the FMR1 gene cause fragile X syndrome? What are my risks of passing a defective FMR1 gene to the next generation?

Learn More
Avada Admin

The Results

How will I receive my results? How long will testing take? What are the possible results and what are the interpretations for each result type?

Learn More

Get Started


Are you ready to get started? Print out this form and take it to your next doctor’s appointment to initiate a conversation with your doctor about Horizon carrier screening.

Order Test Kit


Are you ready to get started? Visit our account setup page to begin offering Horizon in your practice.


Fragile X Syndrome Learning Center

What are the signs and symptoms of Fragile X Syndrome?

The signs and symptoms of fragile X syndrome can involve cognitive, developmental, behavioral and physical aspects, and vary in severity among individuals. This disorder generally affects males more frequently and severely than females. Cognitive People [...]

What are Fragile X-associated disorders?

Fragile X-associated disorders are a group of genetic disorders caused by genetic mutations in the FMR1 (Fragile X Mental Retardation 1) gene, which is responsible for cognitive development and female reproductive functions. There are three [...]

Read More