Study of Intrathecal ELP-02 for Charcot-Marie-Tooth Disease Type 4J (CMT4J)

Inclusion Criteria: * Male and females between the ages of 3 and 20 years at the time of screening. * Molecularly-confirmed diagnosis of CMT4J (confirmed by a CLIA certified, CE-marked, or equivalent lab) due to bi-allelic pathogenic variants (by ACMG criteria) in the FIG4 gene where one of the mutations must be the pathogenic I41T variant, with the second mutation either being another pathogenic or likely pathogenic variant (by ACMG criteria). * Clinical signs and symptoms consistent with CMT4J disease/motor symptoms * No more than moderate severity of the disease as measured by a CMTPeds score of \<35 * Written informed consent provided by subject/parent/guardian and willingness to participate and comply with all the study related visits and procedures. Assent provided by children 10 to 17 years old based on their ability to understand the risks and possible benefits, and the activities expected of them. * Subjects able to reproduce must use a barrier method of contraception for the first 12 months after dosing as well as at least one additional acceptable birth control method if sexually active * Male subjects must agree not to donate sperm for the remainder of their lifetime after receiving ELP-02 * Female subjects must agree not to donate eggs for the remainder of their lifetime after receiving ELP-02 Exclusion Criteria: * Prior or ongoing medical condition, medical history, physical findings, cardiovascular/ECG findings, or laboratory abnormality that, in the investi…