This is a pilot open-label study to evaluate the feasibility of conducting a clinical trial using sublingual dexmedetomidine sublingual film to treat hyperadrenergic autonomic crises in patients with Familial Dysautonomia at home. The primary aims are to examine the feasibility of performing a clinical trial using dexmedetomidine at home to terminate autonomic crisis, and refine the interventions and assessments used to evaluate autonomic crisis termination.

Inclusion Criteria:

• Genetically confirmed diagnosis of Familial Dysautonomia.
• Evidence of autonomic crisis, previous treatment with IV dexmedetomidine without significant side effects, and registered medical data within the year preceding the study in our database.
• One or more autonomic crises during the last year.
• Age above 18 years.
• The patient has a responsible caretaker to communicate with the medical providers.
• Provision of signed and dated informed consent form from the patient and responsible caregiver.
• Able to state willingness to comply with all study procedures and availability for the duration of the study
• For males and females of reproductive potential: use condoms for contraception if sexually active.

Exclusion Criteria:

• At the consideration of the principal investigator, the caregiver cannot fully understand the protocol or communicate during the crisis with the Center.
• The patient during the crisis, before taking the medication, has any of the following:
• a. Oxygen saturation less than 92% on room air or baseline need for oxygen, change from baseline oxygen dependency.
• b. Respiratory rate >20 breaths per minute.
• c. Supine blood pressure ≤ 90/60mmHg
• d. Febrile illness with temperature >100.3 F.
• e. Serological signs of infection (WBC count >10 g/dL, or CRP >10 mg/L or ESR>20, or above their steady historical baseline levels) in recent (less than one month) studies.
• The patient is a female and has a positive pregnancy test.
• MoCA score <25 points.

The de-identified participant data from the final research dataset used in the published manuscript will be shared upon reasonable request beginning 9 months and ending 36 months following article publication or as required by a condition of awards and agreements supporting the research provided the investigator who proposes to use the data executes a data use agreement with NYU Langone Health. Requests may be directed to: Alejandra.gonzalez-duarte@nyulangone.org. The protocol and statistical analysis plan will be made available on Clinicaltrials.gov only as required by federal regulation or as a condition of awards and agreements supporting the research

Beginning 9 months and ending 36 months following article publication or as required by a condition of awards and agreements supporting the research.

The investigator who proposed to use the data will be provided access upon reasonable request. Requests should be directed to Alejandra.gonzalez-duarte@nyulangone.org. To gain access, data requestors will need to sign a data access agreement.