A Novel Synonymous Variant in SQSTM1 Causes Neurodegeneration With Ataxia, Dystonia, and Gaze Palsy Revealed by Urine‐Derived Cells‐Based Functional Analysis

ABSTRACT Background Heterozygous variants of sequestosome‐1 gene (SQSTM1) have been reported in patients with various neurological disorders, whereas biallelic pathogenic variants of SQSTM1 can cause child‐onset and multisystem neurodegeneration, including cerebellar ataxia, dystonia, and vertical g...

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Main Authors: Shinji Masuko, Mitsuto Sato, Katsuya Nakamura, Kohei Hamanaka, Satoko Miyatake, Yuji Inaba, Tomoki Kosho, Naomichi Matsumoto, Yoshiki Sekijima
Format: Article
Language:English
Published: Wiley 2024-11-01
Series:Molecular Genetics & Genomic Medicine
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Online Access:https://doi.org/10.1002/mgg3.70044
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author Shinji Masuko
Mitsuto Sato
Katsuya Nakamura
Kohei Hamanaka
Satoko Miyatake
Yuji Inaba
Tomoki Kosho
Naomichi Matsumoto
Yoshiki Sekijima
author_facet Shinji Masuko
Mitsuto Sato
Katsuya Nakamura
Kohei Hamanaka
Satoko Miyatake
Yuji Inaba
Tomoki Kosho
Naomichi Matsumoto
Yoshiki Sekijima
author_sort Shinji Masuko
collection DOAJ
description ABSTRACT Background Heterozygous variants of sequestosome‐1 gene (SQSTM1) have been reported in patients with various neurological disorders, whereas biallelic pathogenic variants of SQSTM1 can cause child‐onset and multisystem neurodegeneration, including cerebellar ataxia, dystonia, and vertical gaze palsy (NADGP). Here, we describe two cases of NADGP in a Japanese family. Methods We performed clinical and genetic laboratory evaluations of the two patients and their healthy parents. Results By whole‐exome sequencing, we identified compound heterozygous variants in SQSTM1(NM_003900.5): c.1A>G p.(Met1?) in the initial codon, and c.969G>A, located at the 3′ end of exon 6, which is novel and seemingly a synonymous but is actually a truncating variant causing aberrant splicing. An SQSTM1 protein expression assay using urine‐derived cells (UDCs) demonstrated that both variants (c.1A>G and c.969G>A) were unable to induce normal splicing of premessenger RNA. Cerebellar ataxia is a characteristic manifestation of this disorder; however, brain magnetic resonance imaging studies have not shown significant cerebellar atrophy. Our patients experienced chorea during adolescence. Conclusions Only a few reports have highlighted the presence of chorea; however, our findings suggest that NADGP should be considered as a differential diagnosis of hereditary chorea. This study also demonstrates the utility of UDCs, obtained using noninvasive approaches, in functionally analyzing genetic diseases.
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spelling doaj-art-687cbdd84de047abbf4ec9978d2ca9092025-08-20T02:27:57ZengWileyMolecular Genetics & Genomic Medicine2324-92692024-11-011211n/an/a10.1002/mgg3.70044A Novel Synonymous Variant in SQSTM1 Causes Neurodegeneration With Ataxia, Dystonia, and Gaze Palsy Revealed by Urine‐Derived Cells‐Based Functional AnalysisShinji Masuko0Mitsuto Sato1Katsuya Nakamura2Kohei Hamanaka3Satoko Miyatake4Yuji Inaba5Tomoki Kosho6Naomichi Matsumoto7Yoshiki Sekijima8Department of Medicine (Neurology & Rheumatology) Shinshu University School of Medicine Matsumoto JapanDepartment of Medicine (Neurology & Rheumatology) Shinshu University School of Medicine Matsumoto JapanDepartment of Medicine (Neurology & Rheumatology) Shinshu University School of Medicine Matsumoto JapanDepartment of Human Genetics Yokohama City University Graduate School of Medicine Yokohama JapanDepartment of Human Genetics Yokohama City University Graduate School of Medicine Yokohama JapanDivision of Neuropediatrics Nagano Children's Hospital Azumino JapanCenter for Medical Genetics Shinshu University Hospital Matsumoto JapanDepartment of Human Genetics Yokohama City University Graduate School of Medicine Yokohama JapanDepartment of Medicine (Neurology & Rheumatology) Shinshu University School of Medicine Matsumoto JapanABSTRACT Background Heterozygous variants of sequestosome‐1 gene (SQSTM1) have been reported in patients with various neurological disorders, whereas biallelic pathogenic variants of SQSTM1 can cause child‐onset and multisystem neurodegeneration, including cerebellar ataxia, dystonia, and vertical gaze palsy (NADGP). Here, we describe two cases of NADGP in a Japanese family. Methods We performed clinical and genetic laboratory evaluations of the two patients and their healthy parents. Results By whole‐exome sequencing, we identified compound heterozygous variants in SQSTM1(NM_003900.5): c.1A>G p.(Met1?) in the initial codon, and c.969G>A, located at the 3′ end of exon 6, which is novel and seemingly a synonymous but is actually a truncating variant causing aberrant splicing. An SQSTM1 protein expression assay using urine‐derived cells (UDCs) demonstrated that both variants (c.1A>G and c.969G>A) were unable to induce normal splicing of premessenger RNA. Cerebellar ataxia is a characteristic manifestation of this disorder; however, brain magnetic resonance imaging studies have not shown significant cerebellar atrophy. Our patients experienced chorea during adolescence. Conclusions Only a few reports have highlighted the presence of chorea; however, our findings suggest that NADGP should be considered as a differential diagnosis of hereditary chorea. This study also demonstrates the utility of UDCs, obtained using noninvasive approaches, in functionally analyzing genetic diseases.https://doi.org/10.1002/mgg3.70044GC‐AT intronNADGPSQSTM1UDCurine‐derived cell
spellingShingle Shinji Masuko
Mitsuto Sato
Katsuya Nakamura
Kohei Hamanaka
Satoko Miyatake
Yuji Inaba
Tomoki Kosho
Naomichi Matsumoto
Yoshiki Sekijima
A Novel Synonymous Variant in SQSTM1 Causes Neurodegeneration With Ataxia, Dystonia, and Gaze Palsy Revealed by Urine‐Derived Cells‐Based Functional Analysis
Molecular Genetics & Genomic Medicine
GC‐AT intron
NADGP
SQSTM1
UDC
urine‐derived cell
title A Novel Synonymous Variant in SQSTM1 Causes Neurodegeneration With Ataxia, Dystonia, and Gaze Palsy Revealed by Urine‐Derived Cells‐Based Functional Analysis
title_full A Novel Synonymous Variant in SQSTM1 Causes Neurodegeneration With Ataxia, Dystonia, and Gaze Palsy Revealed by Urine‐Derived Cells‐Based Functional Analysis
title_fullStr A Novel Synonymous Variant in SQSTM1 Causes Neurodegeneration With Ataxia, Dystonia, and Gaze Palsy Revealed by Urine‐Derived Cells‐Based Functional Analysis
title_full_unstemmed A Novel Synonymous Variant in SQSTM1 Causes Neurodegeneration With Ataxia, Dystonia, and Gaze Palsy Revealed by Urine‐Derived Cells‐Based Functional Analysis
title_short A Novel Synonymous Variant in SQSTM1 Causes Neurodegeneration With Ataxia, Dystonia, and Gaze Palsy Revealed by Urine‐Derived Cells‐Based Functional Analysis
title_sort novel synonymous variant in sqstm1 causes neurodegeneration with ataxia dystonia and gaze palsy revealed by urine derived cells based functional analysis
topic GC‐AT intron
NADGP
SQSTM1
UDC
urine‐derived cell
url https://doi.org/10.1002/mgg3.70044
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