Long-read technologies identify a hidden LINE-1/ERV1 insertion in IQCB1 as causative variant for Senior-Løken syndrome

Abstract Senior-Løken syndrome is a rare ciliopathy characterized by retinal dystrophy and nephronophthisis. This autosomal recessive inherited disease is caused by pathogenic variants in several genes, including IQCB1. We present a Senior-Løken case that remained genetically unexplained after routi...

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Main Authors: Suzanne E. de Bruijn, L. Ingeborgh van den Born, Ronny Derks, Lonneke Haer-Wigman, Luke O’Gorman, Frans P. M. Cremers, Ronald van Beek, Alexander Hoischen, Susanne Roosing, Kornelia Neveling
Format: Article
Language:English
Published: Nature Portfolio 2025-04-01
Series:npj Genomic Medicine
Online Access:https://doi.org/10.1038/s41525-025-00490-8
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author Suzanne E. de Bruijn
L. Ingeborgh van den Born
Ronny Derks
Lonneke Haer-Wigman
Luke O’Gorman
Frans P. M. Cremers
Ronald van Beek
Alexander Hoischen
Susanne Roosing
Kornelia Neveling
author_facet Suzanne E. de Bruijn
L. Ingeborgh van den Born
Ronny Derks
Lonneke Haer-Wigman
Luke O’Gorman
Frans P. M. Cremers
Ronald van Beek
Alexander Hoischen
Susanne Roosing
Kornelia Neveling
author_sort Suzanne E. de Bruijn
collection DOAJ
description Abstract Senior-Løken syndrome is a rare ciliopathy characterized by retinal dystrophy and nephronophthisis. This autosomal recessive inherited disease is caused by pathogenic variants in several genes, including IQCB1. We present a Senior-Løken case that remained genetically unexplained after routine genetic testing, including exome and genome sequencing. To identify the genetic cause for this individual, a combination of innovative long-read technologies was employed. Using optical genome mapping, an intronic 6.2-kb insertion in IQCB1 was revealed. Validation by long-read genome sequencing determined that this insertion consisted of a LINE-1/ERV1-mobile element. The variant was found in trans with a pathogenic IQCB1 2-bp deletion previously identified by exome sequencing. To investigate the consequences of the insertion, targeted long-read RNA-sequencing was performed, revealing a complex splice defect causing the introduction of a premature stop codon. This finding suggests that mobile element insertions represent a yet underestimated variant type that is difficult to detect using short-read sequencing.
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institution OA Journals
issn 2056-7944
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publishDate 2025-04-01
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series npj Genomic Medicine
spelling doaj-art-413d84ccf2b64a87b41ecedae00490d82025-08-20T02:19:58ZengNature Portfolionpj Genomic Medicine2056-79442025-04-011011510.1038/s41525-025-00490-8Long-read technologies identify a hidden LINE-1/ERV1 insertion in IQCB1 as causative variant for Senior-Løken syndromeSuzanne E. de Bruijn0L. Ingeborgh van den Born1Ronny Derks2Lonneke Haer-Wigman3Luke O’Gorman4Frans P. M. Cremers5Ronald van Beek6Alexander Hoischen7Susanne Roosing8Kornelia Neveling9Department of Human Genetics, Radboud University Medical CenterThe Rotterdam Eye Hospital and Rotterdam Ophthalmic InstituteDepartment of Human Genetics, Radboud University Medical CenterDepartment of Human Genetics, Radboud University Medical CenterDepartment of Human Genetics, Radboud University Medical CenterDepartment of Human Genetics, Radboud University Medical CenterDepartment of Human Genetics, Radboud University Medical CenterDepartment of Human Genetics, Radboud University Medical CenterDepartment of Human Genetics, Radboud University Medical CenterDepartment of Human Genetics, Radboud University Medical CenterAbstract Senior-Løken syndrome is a rare ciliopathy characterized by retinal dystrophy and nephronophthisis. This autosomal recessive inherited disease is caused by pathogenic variants in several genes, including IQCB1. We present a Senior-Løken case that remained genetically unexplained after routine genetic testing, including exome and genome sequencing. To identify the genetic cause for this individual, a combination of innovative long-read technologies was employed. Using optical genome mapping, an intronic 6.2-kb insertion in IQCB1 was revealed. Validation by long-read genome sequencing determined that this insertion consisted of a LINE-1/ERV1-mobile element. The variant was found in trans with a pathogenic IQCB1 2-bp deletion previously identified by exome sequencing. To investigate the consequences of the insertion, targeted long-read RNA-sequencing was performed, revealing a complex splice defect causing the introduction of a premature stop codon. This finding suggests that mobile element insertions represent a yet underestimated variant type that is difficult to detect using short-read sequencing.https://doi.org/10.1038/s41525-025-00490-8
spellingShingle Suzanne E. de Bruijn
L. Ingeborgh van den Born
Ronny Derks
Lonneke Haer-Wigman
Luke O’Gorman
Frans P. M. Cremers
Ronald van Beek
Alexander Hoischen
Susanne Roosing
Kornelia Neveling
Long-read technologies identify a hidden LINE-1/ERV1 insertion in IQCB1 as causative variant for Senior-Løken syndrome
npj Genomic Medicine
title Long-read technologies identify a hidden LINE-1/ERV1 insertion in IQCB1 as causative variant for Senior-Løken syndrome
title_full Long-read technologies identify a hidden LINE-1/ERV1 insertion in IQCB1 as causative variant for Senior-Løken syndrome
title_fullStr Long-read technologies identify a hidden LINE-1/ERV1 insertion in IQCB1 as causative variant for Senior-Løken syndrome
title_full_unstemmed Long-read technologies identify a hidden LINE-1/ERV1 insertion in IQCB1 as causative variant for Senior-Løken syndrome
title_short Long-read technologies identify a hidden LINE-1/ERV1 insertion in IQCB1 as causative variant for Senior-Løken syndrome
title_sort long read technologies identify a hidden line 1 erv1 insertion in iqcb1 as causative variant for senior loken syndrome
url https://doi.org/10.1038/s41525-025-00490-8
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