CureLBSL (formerly A Cure for Ellie)
Cycle 2
Leukoencephalopathy with Brainstem and Spinal Cord Involvement and Lactate Elevation (LBSL) is a very rare and degenerative genetic brain and spinal cord disorder. It slowly robs people of their ability to walk, then stand, then coordinate all motor movements.
Last updated 04/30/2026
Clinical
Disease Class
Genetic diseases
Leukodystrophies and white matter disorders
Mitochondrial disease
Neurological diseases
Body Systems
Metabolic
Muscular / Skeletal
Nervous / Sensory
Organs
Brain
Muscles
Nerves
Spinal cord
Known Genetic Link
Yes, one or more genes directly cause the condition
Causative Genes
DARS2
Contributory Genes
None specified / unknown
Type of Inheritance
Autosomal recessive
Newborn Screening
No
Disease Mechanism(s)
Mitochondrial disorder
Myelination defect
tRNA charging/aminoacylation defect (aminoacyl-tRNA synthetase disorders)
Age of Onset
Adolescence (12-17)
Adulthood (age 18-64)
Early childhood (age 1+-5)
Infancy (age 0-1)
Middle childhood (6-11)
Prebirth
Average Age at Diagnosis
Early childhood (age 1+-5)
Middle childhood (6-11)
Life Expectancy
Adulthood (age 18-64)
Elderly (age 65+)
Affected Sex(es)
Female
Male
National Prevalence
101-1000
Global Prevalence
1001-10000
National Incidence
Less than 10
Global Incidence
Less than 10
Populations and/or ancestry with higher prevalence
Brazil, Finland, Baltics, Russia, Ashkenzai Jewish
Symptoms / Phenotypes
abnormal brain features
anxiety
autonomic nervous system problems
balance problems
breathing difficulties
cognitive impairment / confusion / brain fog
constipation
cramps
depression
developmental delay
dysarthria
dysphagia
excessive hunger / hyperphagia
failure to thrive
fatigue
feeding difficulties
functional motor deficit
gait abnormalities / gait disturbance
headaches / migraines
hypotonia
intellectual delay / global developmental delay
microcephaly
movement disorders / ataxia / tremor
muscle stiffness
muscle weakness
myalgia / muscle pain
nystagmus
peripheral neuropathy
respiratory insufficiency / respiratory failure
seizures / epilepsy
sleep disorders
spasticity
speech problems / apraxia
vision problems
vitamin deficiency
Biomarkers
Diagnostic
· clinical diagnosis of LBSL can be established in a proband with characteristic abnormalities observed on brain and spinal cord MRI using MRI-based criteria. The molecular diagnosis can be established in a proband with suggestive findings and biallelic pathogenic variants in DARS2 identified by molecular genetic testing. If molecular results are inconclusive, a functional assay to identify reduced MtAspRS enzyme activity in lymphoblasts can confirm the diagnosis.
Prognostic
· Leukoencephalopathy with brain stem and spinal cord involvement and lactate elevation (LBSL) is characterized by slowly progressive cerebellar ataxia and spasticity with dorsal column dysfunction (decreased position and vibration sense) in most individuals. The neurologic dysfunction involves the legs more than the arms. The tendon reflexes are retained. Deterioration of motor skills usually starts in childhood or adolescence, but occasionally not until adulthood. Dysarthria develops over time. Occasional findings include epilepsy; learning problems; cognitive decline; and reduced consciousness, neurologic deterioration, and fever following minor head trauma.
Existing Therapies
Complementary and Alternative treatments
· Mitochondrial cocktail composed of antioxidants and amino acids
Expanded access (Compassionate Use)
Other
· Supportive care
Therapies in Development
Antisense oligonucleotide (ASO) therapy
Gene therapy
· 1 - DARS2-AAV9
Repurposed drug
· 2 - Aminolevulinate plus ferrous iron (ALA/Fe), sepiapterin
Therapeutic Development Stages
In preclinical development
Therapeutic Development Role
Funding
Meetings with regulators (e.g., FDA listening sessions, PFDD meetings)
Outcome measures development
Recruitment and outreach to patients
Recruitment and outreach to trial sites / physicians
Results dissemination (including publications)
Travel coordination
Organizational & Research
Cell Lines
Fibroblasts
iPSCs
Myoblasts
Cell Lines, Institution
Applied StemCell, Inc
Children's Hospital of Orange County (CHOC)
Children’s Hospital of Philadelphia (CHOP)
Kennedy Kreiger
University Cologne
University of Helsinki
Cell Lines, Involvement
Funded
Own
Cell Lines, share
Some of our cell lines are freely available
Disease Model
C. elegans
Mouse
Organoids
Yeast
Zebrafish
Disease Model, Institution
Children’s Hospital of Philadelphia (CHOP)
Kennedy Kreiger
University Cologne
Disease Model, Involvement
Funded
Disease Model, share
Some of our disease models are freely available
Organizational Challenges
N/A, left blank
Clinical Trial Role
Not involved
Biobank, Institution
Children’s Hospital of Philadelphia (CHOP)
Biobank, Involvement
Consulted
Center of Excellence, Institution
None
Registry
No, we do not have a registry and have no plans to create one
Natural History Study
Yes, we have collaborated on a natural history study
Data Collected, Natural History Study
Clinical endpoints (outcomes)
Electronic health records/electronic medical records
Genetic data
Imaging data
Medication usage
Patient-reported data
Prospective data
Retrospective data
Platform, Natural History Study
Other
FDA Patient Listening Session
Yes
FDA Patient-Focused Drug Development (PFDD) Program
Yes
ICD Codes
We use an ICD-10 code capturing the family of diseases to which our disease belongs
Diagnostic Guidelines
No
Clinical/Treatment Guidelines
Yes, we have guidance available on our website
Science Advisory Board Policies
Does not have an SAB
Research Network Policies
Has CRN and willing to share policies
Patient Priority Survey
Yes
Patient Priority Survey, share
Yes, will share
Research Roadmap
Yes we have a Research Roadmap, but will not share policies
International Chapters
None
International Partners
North America
Other International Research Initiatives
Europe
North America