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Le Gall J, Dehainault C, Boutte M, Petitalot A, Caputo SM, Courtois L, Vacher S, Bieche I, Radvanyi F, Pacquement H, Doz F, Lumbroso-Le Rouic L, Gauthier Villars M, Stoppa-Lyonnet D, Lallemand F, Houdayer C, Golmard L. Germline HPF1 retrogene insertion in RB1 gene involved in cancer predisposition. J Med Genet 2023; 61:78-83. [PMID: 37541786 DOI: 10.1136/jmg-2022-109105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 07/23/2023] [Indexed: 08/06/2023]
Abstract
About half of the human genome is composed of repeated sequences derived from mobile elements, mainly retrotransposons, generally without pathogenic effect. Familial forms of retinoblastoma are caused by germline pathogenic variants in RB1 gene. Here, we describe a family with retinoblastoma affecting a father and his son. No pathogenic variant was identified after DNA analysis of RB1 gene coding sequence and exon-intron junctions. However, RB1 mRNA analysis showed a chimeric transcript with insertion of 114 nucleotides from HPF1 gene inside RB1 gene. This chimeric transcript led to an insertion of 38 amino acids in functional domain of retinoblastoma protein. Subsequent DNA analysis in RB1 intron 17 revealed the presence of a full-length HPF1 retrogene insertion in opposite orientation. Functional assay shows that this insertion has a deleterious impact on retinoblastoma protein function. This is the first report of a full-length retrogene insertion involved in human Mendelian disease leading to a chimeric transcript and a non-functional chimeric protein. Some retrogene insertions may be missed by standard diagnostic genetic testing, so contribution of retrogene insertions to human disease may be underestimated. The increasing use of whole genome sequencing in diagnostic settings will help to get a more comprehensive view of retrogenes.
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Affiliation(s)
- Jessica Le Gall
- Department of Genetics, Institut Curie, Paris, France
- Department of Genetics, PSL University, Paris, France
| | - Catherine Dehainault
- Department of Genetics, Institut Curie, Paris, France
- Department of Genetics, PSL University, Paris, France
| | - Matteo Boutte
- Department of Genetics, Institut Curie, Paris, France
- Department of Genetics, PSL University, Paris, France
| | - Ambre Petitalot
- Department of Genetics, Institut Curie, Paris, France
- Department of Genetics, PSL University, Paris, France
| | - Sandrine M Caputo
- Department of Genetics, Institut Curie, Paris, France
- Department of Genetics, PSL University, Paris, France
| | - Laura Courtois
- Department of Genetics, Institut Curie, Paris, France
- Department of Genetics, PSL University, Paris, France
| | - Sophie Vacher
- Department of Genetics, Institut Curie, Paris, France
- Department of Genetics, PSL University, Paris, France
| | - Ivan Bieche
- Department of Genetics, Institut Curie, Paris, France
- Université de Paris, Paris, France
| | - François Radvanyi
- Department of Genetics, PSL University, Paris, France
- Molecular Oncology Team, UMR144, Paris, France
| | - Hélène Pacquement
- Department of Genetics, PSL University, Paris, France
- Oncology Center SIREDO, Institut Curie, Paris, France
| | - François Doz
- Molecular Oncology Team, UMR144, Paris, France
- Oncology Center SIREDO, Institut Curie, Paris, France
| | - Livia Lumbroso-Le Rouic
- Department of Genetics, PSL University, Paris, France
- Department of Ophthalmology, Institut Curie, Paris, France
| | - Marion Gauthier Villars
- Department of Genetics, Institut Curie, Paris, France
- Department of Genetics, PSL University, Paris, France
| | - Dominique Stoppa-Lyonnet
- Department of Genetics, Institut Curie, Paris, France
- Department of Genetics, PSL University, Paris, France
| | - François Lallemand
- Department of Genetics, Institut Curie, Paris, France
- Department of Genetics, PSL University, Paris, France
| | - Claude Houdayer
- Department of Genetics, University Hospital Centre Rouen, Rouen, France
| | - Lisa Golmard
- Department of Genetics, Institut Curie, Paris, France
- Department of Genetics, PSL University, Paris, France
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