A First-in-human Study of the Effects of SRP-1005 in Participants With Huntington's Disease

Key Inclusion Criteria: * Genetically confirmed diagnosis of huntingtin (HTT) cytosine-adenine-guanine repeat length ≥40. * Participant has HD Integrated Staging System (HD-ISS) Stage 2 or Mild Stage 3. At screening, the participant must be classified with the Enroll-HD HD-ISS Modified Calculator as either Stage 2 or Mild Stage 3. * Participants who are of childbearing potential, or with partners of childbearing potential, who are sexually active must agree to use a highly effective method of contraception throughout study participation, and for at least 90 days following the end of study. Key Exclusion Criteria: * Any condition that would compromise the safety or feasibility of lumbar puncture or magnetic resonance imaging (MRI). * Presence of other significant neurological or systemic illnesses. * Current, chronic or active human immunodeficiency virus, hepatitis B/C. * Recent use of investigational agents or HTT-lowering therapies. * Uncontrolled psychiatric illness or substance use disorders. * Pregnancy or lactation. Note: Other inclusion/exclusion criteria apply.