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In-frame deletion in canine PITRM1 is associated with a severe early-onset epilepsy, mitochondrial dysfunction and neurodegeneration

Authors :
Hannes Lohi
Anu Suomalainen
Marjo K. Hytönen
Kaspar Matiasek
Meharji Arumilli
Ileana B. Quintero
Enrico Baruffini
Tarja S. Jokinen
Jonas Donner
Geoffray Monteuuis
Marjukka Anttila
Cristina Dallabona
Laurence A. Bindoff
Christopher B. Jackson
Marco Rosati
Pernilla Syrjä
Riika Sarviaho
Medicum
Department of Medical and Clinical Genetics
Veterinary Biosciences
STEMM - Stem Cells and Metabolism Research Program
Veterinary Genetics
Department of Biochemistry and Developmental Biology
Veterinary Pathology and Parasitology
Antti Sukura / Principal Investigator
Helsinki One Health (HOH)
Departments of Faculty of Veterinary Medicine
Equine and Small Animal Medicine
Institute for Molecular Medicine Finland
Hannes Tapani Lohi / Principal Investigator
Department of Neurosciences
Anu Wartiovaara / Principal Investigator
HUSLAB
Haartman Institute (-2014)
Biosciences
Source :
Human Genetics, 1593–1609
Publication Year :
2021
Publisher :
Springer Berlin Heidelberg, 2021.

Abstract

We investigated the clinical, genetic, and pathological characteristics of a previously unknown severe juvenile brain disorder in several litters of Parson Russel Terriers. The disease started with epileptic seizures at 6 to 12 weeks of age and progressed rapidly to status epilepticus and death or euthanasia. Histopathological changes at autopsy were restricted to the brain. There was severe acute neuronal degeneration and necrosis diffusely affecting the grey matter throughout the brain with extensive intraneuronal mitochondrial crowding and accumulation of amyloid-β (Aβ). Combined homozygosity mapping and genome sequencing revealed an in-frame 6-bp deletion in the nuclear-encoded pitrilysin metallopeptidase 1 (PITRM1) encoding for a mitochondrial protease involved in mitochondrial targeting sequence processing and degradation. The 6-bp deletion results in the loss of two amino acid residues in the N-terminal part of PITRM1, potentially affecting protein folding and function. Assessment of the mitochondrial function in the affected brain tissue showed a significant deficiency in respiratory chain function. The functional consequences of the mutation were modeled in yeast and showed impaired growth in permissive conditions and an impaired respiration capacity. Loss-of-function variants in human PITRM1 result in a childhood-onset progressive amyloidotic neurological syndrome characterized by spinocerebellar ataxia with behavioral, psychiatric and cognitive abnormalities. Homozygous Pitrm1-knockout mice are embryonic lethal, while heterozygotes show a progressive, neurodegenerative phenotype characterized by impairment in motor coordination and Aβ deposits. Our study describes a novel early-onset PITRM1-related neurodegenerative canine brain disorder with mitochondrial dysfunction, Aβ accumulation, and lethal epilepsy. The findings highlight the essential role of PITRM1 in neuronal survival and strengthen the connection between mitochondrial dysfunction and neurodegeneration.

Details

Language :
English
ISSN :
14321203 and 03406717
Volume :
140
Issue :
11
Database :
OpenAIRE
Journal :
Human Genetics
Accession number :
edsair.doi.dedup.....f82aa0a3203ba0a48a91207222a80335