Current Environment:


The objectives of this study are to illustrate the clinical, neuro/electrophysiologic, biochemical, and developmental status and progression of patients with Creatine Transporter Deficiency (CTD) and to evaluate the utility of performance-based and other measures in the CTD population.


Creatine Deficiency, X-linked

Recruitment Status


Detailed Description

This is an observational study designed to determine an appropriate clinical assessment battery for males with CTD, and to evaluate Magnetic resonance spectroscopy (MRS) along with other potential biomarkers. It is designed to explore developmental domains of interest and to examine the feasibility and utility of various neuropsychological assessments to measure domains of interest, and to identify possible endpoints for interventional studies. Study will also explore genotype-phenotype correlations. Clinical adverse events will be monitored throughout the study. This study was previously posted by Lumos Pharma, which has been transferred to Ultragenyx in June 2019.

Eligibility Criteria

Inclusion Criteria:

Subject has genomic confirmation of a pathologic mutation in the SLC6A8 gene.
Subject is able to complete study-related procedures.
Subjects' parents/guardians/caregivers must provide written consent (informed consent) to study-related procedures, and if appropriate, the subject will provide an assent.

Exclusion Criteria:

Subject has had status epilepticus within 3 months of screening.
Subject is unable to comply with the study procedures or with a clinical disease or laboratory abnormality that in the opinion of the investigator would potentially increase the risk of participation.



Min Age

6 Months

Max Age

65 Years

Download Date

November 14, 2022

Principal Investigator


Primary Contact Information

For more information on this trial, visit


For more information and to contact the study team:

Observational Study of Males With Creatine Transporter Deficiency NCT02931682