Participants who have received Lenti-D Drug Product in a parent clinical study (bluebird bio-sponsored clinical studies ALD-102 and ALD-104) and who meet the eligibility criteria for the Study LTF-304 will be followed in this long-term followup study for 13 years (for a total of 15 years of follow-up after drug product infusion in the parent studies).

Participants received a single IV infusion of Lenti-D Drug Product (also known as elivaldogene autotemcel or eli-cel) in either parent Study ALD-102 or ALD-104.

The objectives of this long-term follow-up study are to assess long-term safety and efficacy following completion of participation in parent studies. Vector copy number (VCN) measurement, safety evaluations, disease-specific assessments, and assessments to monitor for long-term complications of autologous transplant are conducted in this study.

The MFDs are loss of communication, cortical blindness, tube feeding, total incontinence, wheelchair dependence, complete loss of voluntary movement.

The NFS is a 25-point score used to evaluate the severity of gross neurologic dysfunction in CALD by scoring 15 symptoms (functional domains) across 6 categories. Listed here are the 15 symptoms followed by their maximal score out of 25 points: a) Hearing / auditory processing problems-1, b) Aphasia / apraxia-1, c) Loss of communication-3, d) Vision impairment /field cut-1, e) Cortical blindness-2, f) Swallowing / other central nervous system (CNS) dysfunctions-2, g) Tube feeding-2, h) Running difficulties / hyperreflexia-1, i) Walking difficulties / spasticity / spastic gait (no assistance)-1, j) Spastic gait (needs assistance)-2, k) Wheelchair dependence-2, l) Complete loss of voluntary movement-3, m) Episodes of incontinence -1, n) Total incontinence-2, o) Nonfebrile seizures-1. A score of "0" denotes absence of clinical signs of cerebral disease. Maximal signs within a domain score the total of all grades within that domain.