Longitudinal Assessment of Atypical Tripeptidyl Peptidase 1 Enzyme Deficiency Patients

April 2, 2026 updated by: Children's Hospital of Orange County

Longitudinal Assessment of Atypical Tripeptidyl Peptidase 1 Enzyme Deficiency (Neuronal Ceroid Lipofuscinosis Type 2) Patients

The purpose of this study is to gather information on the possible symptoms that patients with atypical neuronal ceroid lipofuscinosis type 2 (also known as aTPP1 or atypical tripeptidyl peptidase deficiency) have and how they change over time.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Active, not recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Detailed Description

This study aims characterize the natural history of atypical TPP1 deficiency patients via longitudinal multidisciplinary assessments.

Multifaceted clinical, laboratory, imaging, and diagnostic assessments will be performed at regular intervals upon enrolled aTPP1 deficiency patients, collated, and analyzed over a three-year longitudinal period.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
5

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • California
      • Orange, California, United States, 92868
        • Children's Hospital of Orange County

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

4 years and older (Child, Adult, Older Adult)

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Any patient with documented TPP1 enzymatic deficiency or TPP1 sequence variants with onset of first symptom after 4 years of age

Description

Inclusion Criteria:

  • Any patient with documented TPP1 enzymatic deficiency or TPP1 sequence variants
  • Onset of first symptom after 4 years of age
  • Parental provision of informed consent; child provision of assent (if necessary)

Exclusion Criteria:

  • Any patient with "Classical" TPP1 deficiency (onset of first symptom prior to 4 years of age)
  • Investigator assessment that patient is not suitable candidate to participate in the study

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
CLN2 Disease Severity Scoring
Time Frame: At baseline and every 3 months afterwards, up to 3 years
Modified Hamburg Rating Scale. The rating scale consists of two domains (motor function, language). Within each domain, a score from 0 to 3 is assigned and overall scores are calculated by summing the domain scores for final rating of 0 (severely impaired) to 6 (normal).
At baseline and every 3 months afterwards, up to 3 years
Electroretinogram (ERG)
Time Frame: At baseline and every 6 months afterwards, up to 3 years
Standard ERG will be performed to measure function of cones and rods of the inner and outer photoreceptor layers which amplitudes are typically decreased in classical TPP1 deficiency.
At baseline and every 6 months afterwards, up to 3 years
Optical Coherence Tomography (OCT)
Time Frame: At baseline and every 6 months afterwards, up to 3 years
OCT is non-invasive, quantitative measurement of inner and outer photoreceptor layer thicknesses.
At baseline and every 6 months afterwards, up to 3 years
Gait Assessment
Time Frame: At baseline and every 6 months afterwards, up to 3 years
Gait assessment is acquired utilizing infrared sensors applied to participant's clothing and will include collection of walking speed, cadence, swing phase, stride length and time, walking base width, stance phase, and double limb support phase.
At baseline and every 6 months afterwards, up to 3 years
Brain Magnetic Resonance Imaging (MRI)
Time Frame: At baseline and every 12 months afterwards, up to 3 years
Pre/post-contrast images will be acquired to perform volumetric studies and white matter assessment.
At baseline and every 12 months afterwards, up to 3 years
Electroencephalography (EEG)
Time Frame: At baseline and every 12 months afterwards, up to 3 years
EEG will be obtained and analyzed for changes that may be distinctive for TPP1 deficiency. Evaluation of background activity, mild/moderate/severe slowing for age.
At baseline and every 12 months afterwards, up to 3 years
Electroencephalography (EEG)
Time Frame: At baseline and every 12 months afterwards, up to 3 years
EEG will be obtained and analyzed for changes that may be distinctive for TPP1 deficiency. Interictal discharges: location, focal/generalized, discharge burden.
At baseline and every 12 months afterwards, up to 3 years
Electroencephalography (EEG)
Time Frame: At baseline and every 12 months afterwards, up to 3 years
Seizures.
At baseline and every 12 months afterwards, up to 3 years
Electroencephalography (EEG)
Time Frame: At baseline and every 12 months afterwards, up to 3 years
Photoparoxysmal response: present/absent
At baseline and every 12 months afterwards, up to 3 years
Cognitive Assessment, Wechsler Intelligence Scale for Children version 4 (WISC-IV)
Time Frame: At baseline and every 12 months afterwards, up to 3 years
WISC-IV will generate a full scale of intelligence quotient and five primary index scores: Verbal Comprehension, Visual Spatial, Fluid Reasoning, Working Memory, and Processing Speed. The WAIS-IV is scored by summing the raw scores for each subtest; each raw subtest score is then converted to a scaled scored. They are then combined to create a Full Scale IQ Index score. Test takers will also be given a score on the General Ability Index (GAI).
At baseline and every 12 months afterwards, up to 3 years
CSF Testing
Time Frame: At baseline and every 3 months afterwards, up to 3 years
Standard laboratory testing and biobanking / storage of remaining CSF (via Ommaya if on enzyme replacement; via lumbar puncture if not on enzyme replacement)
At baseline and every 3 months afterwards, up to 3 years

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Children's Hospital of Orange County

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
November 1, 2019

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 1, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
July 22, 2019

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 18, 2019

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
September 23, 2019

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 8, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 2, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 190219

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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