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Hosseinpour S, Razmara E, Heidari M, Rezaei Z, Ashrafi MR, Dehnavi AZ, Kameli R, Bereshneh AH, Vahidnezhad H, Azizimalamiri R, Zamani Z, Pak N, Rasulinezhad M, Mohammadi B, Ghabeli H, Ghafouri M, Mohammadi M, Zamani GR, Badv RS, Saket S, Rabbani B, Mahdieh N, Ahani A, Garshasbi M, Tavasoli AR. A comprehensive study of mutation and phenotypic heterogeneity of childhood mitochondrial leukodystrophies. Brain Dev 2024; 46:167-179. [PMID: 38129218 DOI: 10.1016/j.braindev.2023.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Revised: 12/10/2023] [Accepted: 12/12/2023] [Indexed: 12/23/2023]
Abstract
OBJECTIVE Mitochondrial leukodystrophies (MLs) are mainly caused by impairments of the mitochondrial respiratory chains. This study reports the mutation and phenotypic spectrum of a cohort of 41 pediatric patients from 39 distinct families with MLs among 320 patients with a molecular diagnosis of leukodystrophies. METHODS This study summarizes the clinical, imaging, and molecular data of these patients for five years. RESULTS The three most common symptoms were neurologic regression (58.5%), pyramidal signs (58.5%), and extrapyramidal signs (43.9%). Because nuclear DNA mutations are responsible for a high percentage of pediatric MLs, whole exome sequencing was performed on all patients. In total, 39 homozygous variants were detected. Additionally, two previously reported mtDNA variants were identified with different levels of heteroplasmy in two patients. Among 41 mutant alleles, 33 (80.4%) were missense, 4 (9.8%) were frameshift (including 3 deletions and one duplication), and 4 (9.8%) were splicing mutations. Oxidative phosphorylation in 27 cases (65.8%) and mtDNA maintenance pathways in 8 patients (19.5%) were the most commonly affected mitochondrial pathways. In total, 5 novel variants in PDSS1, NDUFB9, FXBL4, SURF1, and NDUSF1 were also detected. In silico analyses showed how each novel variant may contribute to ML pathogenesis. CONCLUSIONS The findings of this study suggest whole-exome sequencing as a strong diagnostic genetic tool to identify the causative variants in pediatric MLs. In comparison between oxidative phosphorylation (OXPHOS) and mtDNA maintenance groups, brain stem and periaqueductal gray matter (PAGM) involvement were more commonly seen in OXPHOS group (P value of 0.002 and 0.009, respectively), and thinning of corpus callosum was observed more frequently in mtDNA maintenance group (P value of 0.042).
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Affiliation(s)
- Sareh Hosseinpour
- Department of Pediatric Neurology, Vali-e-Asr Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Ehsan Razmara
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Morteza Heidari
- Myelin Disorders Clinic, Division of Pediatric Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Zahra Rezaei
- Myelin Disorders Clinic, Division of Pediatric Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahmoud Reza Ashrafi
- Myelin Disorders Clinic, Division of Pediatric Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Zare Dehnavi
- Myelin Disorders Clinic, Division of Pediatric Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, MN 55905, USA
| | - Reyhaneh Kameli
- Department of Cell and Molecular Biology & Microbiology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran
| | - Ali Hosseini Bereshneh
- Prenatal Diagnosis and Genetic Research Center, Dastgheib Hospital, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Hassan Vahidnezhad
- Center for Applied Genomics, Children's Hospital of Philadelphia, Philadelphia, USA; Department of Pediatrics, The University of Pennsylvania School of Medicine, Philadelphia, USA
| | - Reza Azizimalamiri
- Department of Pediatric Neurology, Golestan Medical, Educational, and Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Zahra Zamani
- MD, MPH, Community Medicine Specialist, Tehran University of Medical Sciences, Tehran, Iran
| | - Neda Pak
- Department of Radiology, Children's Hospital Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Rasulinezhad
- Myelin Disorders Clinic, Division of Pediatric Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Bahram Mohammadi
- Myelin Disorders Clinic, Division of Pediatric Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Homa Ghabeli
- Myelin Disorders Clinic, Division of Pediatric Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Ghafouri
- Myelin Disorders Clinic, Division of Pediatric Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahmoud Mohammadi
- Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Gholam Reza Zamani
- Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Reza Shervin Badv
- Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Sasan Saket
- Iranian Child Neurology Center of Excellence, Pediatric Neurology Research Center, Research Institute for Children Health, Mofid Children's and Shohada-e Tajrish Hospitals, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Bahareh Rabbani
- Growth and Development Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Nejat Mahdieh
- Growth and Development Research Center, Tehran University of Medical Sciences, Tehran, Iran; Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Ali Ahani
- Mendel Medical Genetics Laboratory, Iran University of Medical Sciences, Tehran, Iran
| | - Masoud Garshasbi
- Department of Medical Genetics, Faculty of Medical Sciences, Jalal-Al Ahmad Hwy, Tarbiat Modares University, Tehran, Iran.
| | - Ali Reza Tavasoli
- Myelin Disorders Clinic, Division of Pediatric Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran; Neurology Division, Barrow Neurological Institute, Phoenix Children's Hospital, Phoenix, AZ, USA.
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