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Mendeliome v0.8583 PRDX3 Hazel Phillimore changed review comment from: Biallelic variants in 5 unrelated families with early onset (median 21 years , range 13-22 years) with ataxia with variable additional hyper- and hypokinetic movement disorders, and severe early-onset cerebellar atrophy (seen on MRI), and involvement of the brainstem, medullary olive and parietal cortex.
Evolution of the disease was gait ataxia leading to upper limb ataxia, then dysarthria and then dysphagia, all within a decade. For some of these patients, the phenotype included myoclonus, dystonia and / or tremor. Mild classical mitochondrial features were seen in one of the patients, namely ptosis and COX-negative fibres.
The variants were homozygous nonsense, homozygous frameshift, homozygous missense, and a compound heterozygote of a splice variant and missense, all leading to complete loss of the protein. Oxidative stress and mitochondrial dysfunction was indicated as the disease mechanism.
The families originated from Germany, France, India and two from eastern Turkey. The two families from Turkey were seemingly unrelated to each other but had the same homozygous missense.
Patient fibroblasts from each of the five probands showed lack of protein (via Western blot) and decreased glutathione peroxidase activity and decreased mitochondrial maximal respiratory capacity.
PRXD3 encodes peroxiredoxin 3, a mitochondrial antioxidant protein, that catalyses the reduction of hydrogen peroxide. It localises in the mitochondria, where most hydrogen peroxide is generated.
Functional studies: PRDX3 knockdown (induced by silencing RNA against PRDX3) in cerebellar medulloblastoma cells showed significantly decreased cell viability, increased hydrogen peroxide levels and increased susceptibility to apoptosis triggered by reactive oxygen species.
In addition, induced knockdown drosophila (in vivo animal model) had aberrant locomotor phenotypes and reduced lifespans, while immunolabelling of the brain showed increased cell death after exposure to oxidative stress.
Sources: Literature; to: Biallelic variants in 5 unrelated families with early onset (median 21 years , range 13-22 years) with ataxia with variable additional hyper- and hypokinetic movement disorders, and severe early-onset cerebellar atrophy (seen on MRI), and involvement of the brainstem, medullary olive and parietal cortex.
Evolution of the disease was gait ataxia leading to upper limb ataxia, then dysarthria and then dysphagia, all within a decade. For some of these patients, the phenotype included myoclonus, dystonia and / or tremor. Mild classical mitochondrial features were seen in one of the patients, namely ptosis and COX-negative fibres.
The variants were homozygous nonsense, homozygous frameshift, homozygous missense, and a compound heterozygote with a splice variant and missense, all leading to complete loss of the protein. Oxidative stress and mitochondrial dysfunction was indicated as the disease mechanism.
The families originated from Germany, France, India and two from eastern Turkey. The two families from Turkey were seemingly unrelated to each other but had the same homozygous missense.
Patient fibroblasts from each of the five probands showed lack of protein (via Western blot) and decreased glutathione peroxidase activity and decreased mitochondrial maximal respiratory capacity.
PRDX3 encodes peroxiredoxin 3, a mitochondrial antioxidant protein, that catalyses the reduction of hydrogen peroxide. It localises in the mitochondria, where most hydrogen peroxide is generated.
Functional studies: PRDX3 knockdown (induced by silencing RNA against PRDX3) in cerebellar medulloblastoma cells showed significantly decreased cell viability, increased hydrogen peroxide levels and increased susceptibility to apoptosis triggered by reactive oxygen species.
In addition, induced knockdown drosophila (in vivo animal model) had aberrant locomotor phenotypes and reduced lifespans, while immunolabelling of the brain showed increased cell death after exposure to oxidative stress.
Sources: Literature
Mendeliome v0.8583 PRDX3 Hazel Phillimore gene: PRDX3 was added
gene: PRDX3 was added to Mendeliome. Sources: Literature
Mode of inheritance for gene: PRDX3 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: PRDX3 were set to PMID: 33889951
Phenotypes for gene: PRDX3 were set to cerebellar ataxia (early onset, mild to moderate, progressive)
Penetrance for gene: PRDX3 were set to unknown
Review for gene: PRDX3 was set to GREEN
Added comment: Biallelic variants in 5 unrelated families with early onset (median 21 years , range 13-22 years) with ataxia with variable additional hyper- and hypokinetic movement disorders, and severe early-onset cerebellar atrophy (seen on MRI), and involvement of the brainstem, medullary olive and parietal cortex.
Evolution of the disease was gait ataxia leading to upper limb ataxia, then dysarthria and then dysphagia, all within a decade. For some of these patients, the phenotype included myoclonus, dystonia and / or tremor. Mild classical mitochondrial features were seen in one of the patients, namely ptosis and COX-negative fibres.
The variants were homozygous nonsense, homozygous frameshift, homozygous missense, and a compound heterozygote of a splice variant and missense, all leading to complete loss of the protein. Oxidative stress and mitochondrial dysfunction was indicated as the disease mechanism.
The families originated from Germany, France, India and two from eastern Turkey. The two families from Turkey were seemingly unrelated to each other but had the same homozygous missense.
Patient fibroblasts from each of the five probands showed lack of protein (via Western blot) and decreased glutathione peroxidase activity and decreased mitochondrial maximal respiratory capacity.
PRXD3 encodes peroxiredoxin 3, a mitochondrial antioxidant protein, that catalyses the reduction of hydrogen peroxide. It localises in the mitochondria, where most hydrogen peroxide is generated.
Functional studies: PRDX3 knockdown (induced by silencing RNA against PRDX3) in cerebellar medulloblastoma cells showed significantly decreased cell viability, increased hydrogen peroxide levels and increased susceptibility to apoptosis triggered by reactive oxygen species.
In addition, induced knockdown drosophila (in vivo animal model) had aberrant locomotor phenotypes and reduced lifespans, while immunolabelling of the brain showed increased cell death after exposure to oxidative stress.
Sources: Literature
Mendeliome v0.7699 PRX Zornitza Stark Marked gene: PRX as ready
Mendeliome v0.7699 PRX Zornitza Stark Gene: prx has been classified as Green List (High Evidence).
Mendeliome v0.7699 PRX Zornitza Stark Phenotypes for gene: PRX were changed from to Charcot-Marie-Tooth disease, type 4F, MIM# 614895; Dejerine-Sottas disease, MIM# 145900
Mendeliome v0.7698 PRX Zornitza Stark Publications for gene: PRX were set to
Mendeliome v0.7697 PRX Zornitza Stark Mode of inheritance for gene: PRX was changed from Unknown to BIALLELIC, autosomal or pseudoautosomal
Mendeliome v0.7696 PRX Zornitza Stark reviewed gene: PRX: Rating: GREEN; Mode of pathogenicity: None; Publications: 11133365, 11157804, 15197604, 21079185, 22847150, 10839370, 32460404, 31523542, 31426691; Phenotypes: Charcot-Marie-Tooth disease, type 4F, MIM# 614895, Dejerine-Sottas disease, MIM# 145900; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Mendeliome v0.0 PRX Zornitza Stark gene: PRX was added
gene: PRX was added to Mendeliome_VCGS. Sources: Expert Review Green,Victorian Clinical Genetics Services
Mode of inheritance for gene: PRX was set to Unknown