An observational study in Neurodegenerative Disease, Hereditary, Mitochondrial Diseases and Optic Atrophy, sponsored by State University of New York at Buffalo. Completed at 1 site in United States. Open to participants aged 0 Years to 65 Years. Per ClinicalTrials.gov, last updated 2024-03-08.
Sponsored by State University of New York at Buffalo · Observational
The purpose of the study is to systematically characterize the clinical course of the progressive neuropathy and optic atrophy observe in pediatric and adult patients with biallelic mutations in the solute carrier family 25 member 46 (SLC25A46) gene.
The number of mitochondria in the cell is dynamic and is regulated by two opposite processes, namely fission and fusion. Proteins in both the inner mitochondrial membrane (IMM) and the outer mitochondrial membrane (OMM) are involved in mediating these two processes, including OPA1, MFN2 and SLC25A46. Recent work by the investigators as well as other research groups has shown that mutations in SLC25A46 cause abnormal mitochondrial fusion, leading to optic nerve atrophy, axonal peripheral neuropathy and cerebellar degeneration by interfering with mitochondrial fission. Recently, the investigators have used CRISPR genome editing to generate a global Slc25a46 KO mouse model with complete loss of SLC25A46 in all tissues (PMID: 28934388). Similar to patients with biallelic mutations in SLC25A46, these mice exhibit severe ataxia, optic atrophy, peripheral neuropathy related to axonal degeneration, and demyelination due to mitochondrial hyperfusion and defective energy production. In these mice, histological staining revealed a hypotrophic cerebellum with a severe loss of Purkinje cells (PCs) and/or stunted PC dendrites while electron microscopy revealed enlarged mitochondria with swollen cristae and other abnormal morphologies in PC dendrites and sciatic nerves. Furthermore, in primary culture, PCs from these mice exhibited abnormal mitochondrial distribution and movement.
These findings provide compelling evidence indicating that SLC25A46 plays an important role in the regulation of mitochondrial dynamics-including fusion/fission, distribution, and movement, as well as the maintenance of cristae architecture-and that loss of SLC25A46 function has a particularly severe effect on a distinct subset of neuron types with long axonal processes. More recently, the investigators have shown that AAV-based gene therapy can produce dramatic improvements in their Slc25a46 mutant mouse model (PMID: 31943007). These studies in the Slc25a46 mouse model provide the foundation for uncovering the mechanism whereby these this gene causes disease in humans, as well as lay the groundwork for the possible use of gene therapy to ameliorate the disease phenotype in patients.
However, despite this progress, there remains only a handful of studies published on Slc25a46 and the consequences of loss of Slc25a46 function in humans. Given that human SLC25A46-associated phenotypes overlap substantially with DOA and CMT2A, further study of this rare condition presents an opportunity not only to better understand and treat SLC25A46-related disease, but also to elucidate the broader mechanistic link between neurodegeneration and abnormal mitochondrial dynamics. Thus, in order to better understand the clinical manifestations of SLC25A46-related disease and to help lay the groundwork for eventual clinical trials of gene therapy or drug-based treatments, the investigators propose this natural history study of pediatric as well as adult patients with biallelic mutations in the SLC25A46 gene.
21 studies on the registry are indexed under Heredodegenerative Disorders, Nervous System; 5 are open to participants now.
Browse Heredodegenerative Disorders, Nervous System studies →State University of New York at Buffalo is the lead sponsor of 294 studies on the registry; 63 are open to participants now.
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Primary care clinic
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Male and female patients from age 2 to age 65 with clinically confirmed SLC25A46 mutations. Both living and deceased patients will be included, if eligible. For deceased patients, the patient's medical history records will be reviewed, and an interview of the parent(s) or caregiver(s) will be performed.
Genetic: Mutation analysis
The investigators will sequence DNA samples from the patients or their families.
Custom Medical History Questionnaire for Patients with SLC25A46 Mutation-related Mitochondriopathy
In addition to a standard medical history, patients or their legal guardians will be asked to complete a custom medical history questionnaire tailored toward conditions commonly observed in patients with biallelic SLC25A46 mutations. The items that will be asked about in this questionnaire are as follows: 1. Known mutations in SLC25A46 2. Any family history of illness 3. Complications of pregnancy 4. Premature birth 5. Complications with birth 6. Developmental delay 7. Developmental regression 8. Abnormal size of brain 9. Movement disorders (ataxia, dystonia, etc.) 10. Seizures 11. Optic atrophy in eye exam 12. Vision loss 13. Other vision problems (color, eye movement) 14. Hypotonia (muscle weakness or lack of tone) 15. Electromyogram (EMG) 16. Muscle biopsy 17. Spasticity (muscle stiffness or tightness) 18. Brain MRI performed? 19. Electroencephalogram (EEG)
Time frame: 3 years
Retrospective examination of the medical records of patients with SLC25A46 Mutation-related Mitochondriopathy
With the informed consent of the patients or their parent(s) and/or legal guardian(s), the investigators will perform a retrospective examination of the medical records of both living and deceased patients with confirmed biallelic SLC25A46 mutations.
Time frame: 3 years
Eye assessments to evaluate ocular health
Visual acuity examination will be performed to determine the patient's clarity or sharpness of vision.
Time frame: 3 years
Growth and development (height)
World Health Organization (WHO) growth charts will be used to document height in centimeters (cm) for patients ranging from ages 5 to 19 years old. Routine methods will be used to document height for all other age groups.
Time frame: 3 years
Growth and development (weight)
World Health Organization (WHO) growth charts will be used to document weight in kilograms (kg) for pediatric patients age 5 to 10 years old. Routine methods will be used to document weight for all other age groups.
Time frame: 3 years
Growth and development (BMI)
World Health Organization (WHO) growth charts will be used to document Body Mass Index (BMI) in kilograms per meter square for patients age 5 to 19 years old. Routine methods will be used to document BMI for all other age groups.
Time frame: 3 years
Plan to share: No
Ran from Nov 2020 to primary completion in Aug 2023, 33 months.
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This study is completed, as verified in Mar 2024. You cannot join it, but the record below documents what was studied.
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Heredodegenerative Disorders, Nervous System →
State University of New York at Buffalo →