Diagnostic Testing & Gene Sequencing


Prevention Genetics is a US company that offers GAN gene sequencing. You will need to fill out a requisition form that will accompany your DNA specimen. It is important that each biological parent also send blood to Prevention Genetics for gene sequencing, if possible. They will use parental DNA to confirm the GAN mutations identified in the affected child.

Your insurance should cover diagnostic genetic testing. However, your doctor will need to write a letter of medical justification. The link below is a sample letter your doctor can simply edit and send to your insurance carrier. It is often much more efficient for you to work directly with your insurance carrier, as doctors offices are generally very busy, and it may take too long for them to follow-up.

Blood will remain very stable so international patients can also use Prevention Genetics for GAN gene sequencing.


  1. Print or email GAN_letter_of_medical_necessity to either your geneticist or neurologist who will draw the blood for gene sequencing.
  2. Print 3 copies of the requisition form (click here). Fill out one for each person receiving sequencing, including each biological parent and affected child. These forms will be sent to Prevention Genetics along with the DNA (blood) samples.
  3. Request the edited letter of medical necessity from your doctor, and forward it to your insurance company if the doctor’s office hasn’t yet sent it. It is often more efficient to fax information to your insurance company. If your insurance company denies coverage for sequencing, you have up to 3 levels of appeals before an oversight Board who polices insurance companies makes the final decision. Or, you can pay for sequencing out of pocket. The cost per person is around $690.00 US. Once the GAN mutations are known in an affected family member, it costs around $290.00 for a targeted variant test to see if other family members are GAN carriers or themselves have GAN if symptomatic.
  4. Schedule a lab draw appointment with either your geneticist or neurologist. Bring test requisition forms with you.

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