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Completed

NCT Number: NCT03181399

Diet Treatment Glucose Transporter Type 1 Deficiency (G1D)

Forty-five subjects receiving no dietary therapy with a proven G1D diagnosis will be enrolled. To evaluate the effect of C7 supplementation of a regular diet on a EEG activity in addition to IQ, language, working memory, processing speed, emotional and behavioral functioning, ataxia, and other neuropsychological and neurological performance indices in children and adults genetically diagnosed with G1D receiving a regular diet at enrollment.

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Key information

Conditions

GLUT1DS1 Brain Diseases Central Nervous System Diseases Epilepsy Glucose Metabolism Disorders Glucose Transport Defect Glucose Transporter Protein Type 1 Deficiency Syndrome Glucose Transporter Type 1 Deficiency Syndrome Glut1 Deficiency Syndrome Glut1 Deficiency Syndrome 1, Autosomal Recessive Glycogen Storage Disease Id Metabolic Diseases Nervous System Diseases Nutritional and Metabolic Diseases

Age range

24 month–35 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

University of Texas Southwestern Medical Center

Dallas, Texas, 75390, United States

About this study

This is an open-label, single arm trial of orally-administered C7 in G1D. Subjects will replace a fixed percentage of their daily caloric intake (based on the results of Protocol 1) with C7 for 6 months, undergo full evaluation and discontinuation of treatment at a 6 month visit, and return for an off-treatment follow up visit 3 months after C7 oil discontinuation, for total duration of participation of 9 months. Subjects will undergo treatment initiation on a 24-hour inpatient basis. During that 24-hr inpatient treatment initiation, subjects will have continuous EEG both to monitor for real-time seizure activity (for safety) and to determine EEG changes (secondary outcome) before, during, and after treatment initiation. Subjects will undergo clinical evaluation, comprehensive blood work, ataxia scale rating, EEG, and neuropsychological testing at baseline, 6 months, and 9 months.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Diagnosis of glucose transporter type I deficiency (G1D), confirmed by clinical genotyping at a CLIA-certified laboratory or by PET scan.
  • Stable diet on either a modified atkins diet or on no dietary therapy (i.e., no dietary therapy for 1 month).
  • Males and females 24 months to 35 years old, inclusive.

Exclusion criteria

  • Subjects with evidence of independent, unrelated metabolic and/or genetic disease.
  • Subjects with a chronic gastrointestinal disorder, such as irritable bowel syndrome, Crohn's disease, or colitis that could increase the subject's risk of developing diarrhea or stomach pain.
  • Subjects with a BMI (body mass index) greater than or equal to 30.
  • Subjects currently on dietary therapy (i.e., ketogenic diet, medium chain triglyceride supplemented diets, Atkins diet, low glycemic index diet).
  • Subjects with no evidence of abnormal EEG (spike wave discharges) in the last 12 months.
  • Women who are pregnant or breast-feeding may not participate. Women who plan to become pregnant during the course of the study, or who are unwilling to use birth control to prevent pregnancy (including abstinence) may not participate. Females age 10 and over will be asked to provide a urine sample for a pregnancy test via dipstick. Subjects will be asked to agree to abstinence or another form of birth control for the duration of the study.
  • Allergy/sensitivity to C7.
  • Previous use of triheptanoin in the past 1 month. Subjects who participate in Protocol 1 of this study are thus eligible.
  • Subjects exhibiting signs of dementia, or diagnosed with any degenerative brain disorder (such as Alzheimer's disease) that would confound assessment of cognitive changes, in the opinion of the investigator.
  • Active drug or alcohol use or dependence that, in the opinion of the investigator, would interfere with adherence to study requirements.
  • Inability or unwillingness of subject or legal guardian/representative to give written informed consent, or assent for children age 10-17.
  • Addition of a new antiseizure drug in the previous 3 months.

Treatment and study plan

Triheptanoin

Drug

. Triheptanoin will be taken 4 times per day (approximately every 6 hours: prior to breakfast, lunch and dinner and a mid-afternoon snack) by mouth. It is dosed 4 times per day, divided evenly.

Other names: C7

Primary outcomes

  1. Neuropsychological Score of Sustained Attention

    Time frame: Change post 6 months of treatment

    Sustained attention was evaluated using a subtest of Conners' Kiddie Continuous Performance Test Second Edition (K-CPT 2): CPT-Hit Reaction Time Block Change. CPT HRT BC indicates the change in mean response speed as the administration of the test progresses in blocks. A decrease in CPT HRT BC indicates a decrease in reaction time, which means the participant's information processing efficiency increases, and an improvement in sustained attention is noted. The number of participants that showed a decrease in the CPT HRT BC score after 6 months of treatment as compared to baseline is noted here.

  2. Neuropsychological Score of Sustained Attention

    Time frame: Change after 3 months off treatment

    Sustained attention was evaluated using a subtest of Conners' Kiddie Continuous Performance Test Second Edition (K-CPT 2): CPT-Hit Reaction Time Block Change. CPT HRT BC indicates the change in mean response speed as the administration of the test progresses in blocks. A decrease in CPT HRT BC indicates a decrease in reaction time, which means the participant's information processing efficiency increases, and an improvement in sustained attention is noted. The off-treatment period of 3 months was implemented to study whether the impact of treatment persists or goes back to baseline. The number of patients that displayed an increase in CPT HRT BC score (towards baseline) after 3 months off treatment as compared to 6 months on treatment is noted here.

  3. Neuropsychological Score of Working Memory Index Scale (WMI)

    Time frame: Change post 6 months of treatment

    Subjects were administered the Working Memory Index Scale (WMI) from either the Wechsler Primary and Preschool Scale of Intelligence, 4th Edition (WPPSI-IV), Wechsler Intelligence Scale for Children, 5th Edition (WISC-V), or the Wechsler Adult Intelligence Scale, 4th Edition (WAIS-IV) according to the age of subject. An increase WMI score would indicate an improvement in the cognitive ability of identifying, reorganizing and retaining information for a brief period of time. The number of participants that showed an increase in the WMI score after 6 months of treatment is noted here.

  4. Neuropsychological Score of Working Memory Index Scale (WMI)

    Time frame: Change after 3 months off-treatment

    Subjects were administered the Working Memory Index Scale (WMI) from either the Wechsler Primary and Preschool Scale of Intelligence, 4th Edition (WPPSI-IV), Wechsler Intelligence Scale for Children, 5th Edition (WISC-V), or the Wechsler Adult Intelligence Scale, 4th Edition (WAIS-IV) according to the age of subject. An increase WMI score would indicate an improvement in the cognitive ability of identifying, reorganizing and retaining information for a brief period of time. The 3 months off-treatment period was designed to study whether the impact of treatment persists or goes back to baseline. The number of participants that showed a decrease in the WMI score after 3 months off treatment as compared to 6 months on treatment was calculated.

  5. Neuropsychological Score of Processing Speed Index (PSI)

    Time frame: Change post 6 months of treatment

    Subjects were administered the Processing Speed Index Scale (PSI) from either the Wechsler Primary and Preschool Scale of Intelligence, 4th Edition (WPPSI-IV), Wechsler Intelligence Scale for Children, 5th Edition (WISC-V) or the Wechsler Adult Intelligence Scale, 4th Edition (WAIS-IV) according to the age of subject. An increase PSI score would indicate an improvement in the motor-based estimate of the subject's cognitive processing speed. The number of participants that showed an increase in the PSI score after 6 months of treatment as compared to baseline is noted here.

  6. Neuropsychological Score of Processing Speed Index (PSI)

    Time frame: Change after 3 months off-treatment

    Subjects were administered the Processing Speed Index Scale (PSI) from either the Wechsler Primary and Preschool Scale of Intelligence, 4th Edition (WPPSI-IV), Wechsler Intelligence Scale for Children, 5th Edition (WISC-V) or the Wechsler Adult Intelligence Scale, 4th Edition (WAIS-IV) according to the age of subject. An increase PSI score would indicate an improvement in the motor-based estimate of the subject's cognitive processing speed. The 3 months off-treatment period was designed to study whether the impact of treatment persists or goes back to baseline. The number of participants that showed a decrease in the WMI score after 3 months off treatment as compared to 6 months on treatment was calculated.

Secondary outcomes

  1. EEG Changes: Generalized Spike Wave Activity and Burst

    Time frame: Change post 6 months of treatment

    The number of generalized spike wave (GSW) activity and bursts were extracted from the patient EEGs. GSW and bursts per hour was calculated. A decrease in the spike wave and burst indicated an improvement. The number of patients that displayed a decrease in GSW and burst per hour after 6 months of treatment in noted here.

  2. EEG Changes: Generalized Spike Wave Activity and Burst

    Time frame: Change after 3 months off-treatment

    The number of generalized spike wave (GSW) activity and bursts were extracted from the patient EEGs. GSW and bursts per hour was calculated. A decrease in the spike wave and burst indicated an improvement. The off-treatment period of 3 months was implemented to study whether the impact of treatment persists or goes back to baseline. The number of patients that displayed an increase in GSW and burst per hour (towards baseline) after 3 months off treatment as compared to 6 months on treatment is noted here.

  3. Brief Ataxia Rating Scale

    Time frame: Change post 6 months of treatment

    Ataxia is scored as per the Brief ataxia rating scale (BARS) - a modified form of the International Cooperative Ataxia Rating Scale (ICARS). The possible range for the scores is from 0 (normal, no ataxia) to 30 (severe ataxia). A decrease in the BARS score indicates an improvement in the ataxia symptoms. The number of participants that showed a decrease in BARS score after 6 months of intervention is reported here.

  4. Brief Ataxia Rating Scale

    Time frame: Change after 3 months off treatment

    Ataxia is scored as per the Brief ataxia rating scale (BARS) - a modified form of the International Cooperative Ataxia Rating Scale (ICARS). The possible range for the scores is from 0 (normal, no ataxia) to 30 (severe ataxia). A decrease in the BARS score indicates an improvement in the ataxia symptoms. The off-treatment period of 3 months was implemented to study whether the impact of treatment persists or goes back to baseline. The number of participants that showed a subsequent increase in BARS score (towards baseline) after the of 3 months of no treatment as compared to 6 months on treatment are recorded here.

  5. Clinical Global Impression Severity Scale

    Time frame: Change post 6 months of treatment

    The Clinical global impression - Severity (CGI-S) scale is used to evaluate the illness severity where the scores range from 1 (very much improved) through to 7 (very much worse). A decrease in the CGI-S score indicates a decrease in illness severity. The number of participants that showed a decrease in CGI-S score after 6 months of intervention as compared to baseline is reported here.

  6. Clinical Global Impression Severity Scale

    Time frame: Change after 3 months off-treatment

    The Clinical global impression - Severity (CGI-S) scale is used to evaluate the illness severity where the scores range from 1 (very much improved) through to 7 (very much worse). A decrease in the CGI-S score indicates a decrease in illness severity. The off-treatment period of 3 months was designed to study whether the impact of treatment persists or goes back to baseline. The number of participants that showed an increase in CGI-S score (towards baseline) after 3 months off treatment as compared to 6 months on treatment is reported

Sponsors and collaborators

Lead sponsor

University of Texas Southwestern Medical Center

Other

Collaborators

  • National Institute of Neurological Disorders and Stroke (NINDS)

Registry information

Official study title

Dietary Treatment of Glucose Transporter Type 1 Deficiency (G1D)

Important dates

Study start
2018
Primary completion
2023
Study completion
2023
First posted
Jun 8, 2017
Registry last updated
Aug 7, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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