WHO: The investigators are recruiting children and young adults to participate in a research study who:

1. Have been diagnosed with Alternating Hemiplegia of Childhood (AHC)
2. Are between the ages of 6 months - 25 years old
3. Have at least three 10-minute-long AHC episodes during a typical week
4. Can commit to 12 weeks of completing of a daily log describing AHC episodes and to a multi-night hospital stay at the University of Utah Center for Clinical and Translational Science (CCTS)

WHY: The goal of this study is to evaluate whether the study drug can safely and effectively decrease AHC episodes and improve the quality of life of individuals with AHC.

WHAT and WHERE: This study involves at least 12 weeks of completing and submitting daily AHC Episode Logs and a five-day hospital stay at the University of Utah CCTS.

There are 4 phases of the study, and they include:

1. Six weeks of daily log completion prior to starting study drug
2. Five day stay at the University of Utah CCTS
3. Six additional weeks of daily log completion while using study drug at home
4. One day clinic visit to the University of Utah for follow up

COMPENSATION:

There is no fee to participate. All procedures performed specifically for this study will be covered by the study and will not be billed to you or your insurance company.

The study drug will be dispensed to you free of charge. Meals and lodging at the study site will be provided free of charge for the study participant and one care provider. Additionally, the research team will assist subjects with booking and obtaining free transportation, such as an airline tickets, to and from the study site.

Inclusion Criteria:

Subjects must meet all of the following inclusion criteria.

• AHC classic criteria:

  • Onset of symptomatology prior to 18 months of age
  • Repeated attacks of hemiplegia involving either side of the body
  • Paroxysmal disturbances, including tonic or dystonic spells, oculomotor abnormalities, and various autonomic phenomena, during hemiplegic bouts or in isolation
  • Episodes of bilateral hemiplegia or quadriplegia starting either as generalization of a hemiplegic episode or bilateral from the beginning
  • Immediate disappearance of symptoms upon sleeping, with possible resumption 10-20 minutes after waking
  • Evidence of developmental delay and neurologic abnormalities including choreoathetosis, dystonia, or ataxia

In addition:

• Provision of a complete daily event log for 6 weeks prior to initiation of sodium oxybate therapy, including the: (1) frequency, (2) duration, (3) type, (4) severity of episodes, and (5) therapies, if any, used in an attempt to abort the episode
• Ages 6 months to 25 years at the time of study enrollment
• Minimum of 3 AHC episodes weekly, lasting at least 10 minutes each, on average prior to study enrollment
• Brain neuroimaging studies excluding alternative etiology for symptoms
• Documented absence of epileptiform features on EEG during typical ictal events
• Ability of primary caregivers of study participants to submit online daily AHC Episode Logs indicating frequency and duration of ictal episodes over the entire study period
• Written informed consent from parents/guardians and assent from children 7 years or older
• Girls/women > 12 years of age will be required to be on birth control continuously if they are considered at risk to become pregnant. Those not on birth control will be required to have a screening pregnancy test at baseline, and to confirm their willingness to practice birth control or abstain from sexual activity for the duration of treatment with study medication.

Exclusion Criteria:

Subjects who meet any of the following criteria will be excluded from participation.

• History of hepatic insufficiency, renal insufficiency, significant respiratory disease, cardiac arrhythmia, congenital heart defect, hypertension, or ischemic stroke
• History of allergy/sensitivity to sodium oxybate
• Use of sodium oxybate within 30 days of study enrollment
• Serious illness requiring systemic treatment and/or hospitalization within two weeks prior to study enrollment
• Change in neurologic medication regimen within 30 days of study enrollment.
• Inability to stay at the Center for Clinical and Translational Science (CCTS) for 5 days due to behavioral issues
• Unwillingness or inability to travel to study site during the necessary 1 week titration period to determine the most appropriate dose of GHB for subsequent administration
• Noncompliance with AHC Episode Log or study visit requirements
• Sleep apnea not adequately treated with C-PAP and oxygen saturation monitoring prior to drug therapy initiation
• Succinic semialdehyde dehydrogenase deficiency