Genetics of disease, diagnosis and treatmen

Bijlsma, Emilia K.

de Die-Smulders, Christine E.

de Wert, Guido M.

Dondorp, Wybo J.

Losekoot, Moniek

Tibben, Aad

English

Maastricht University Research Portal

   Reply to Oliver W Quarrell et al.Citation for published version (APA):Tibben, A., Dondorp, W. J., de Wert, G. M., de Die-Smulders, C. E., Losekoot, M., & Bijlsma, E. K. (2019).Reply to Oliver W Quarrell et al. "Letter in response to Tibben et al., Risk Assessment for Huntington'sDisease for (Future) Offspring Requires Offering Preconceptional CAG Analysis to Both Partners". Journalof Huntington's disease, 8(3), 361-362. https://doi.org/10.3233/JHD-199004Document status and date:Published: 01/01/2019DOI:10.3233/JHD-199004Document Version:Publisher's PDF, also known as Version of recordDocument license:TavernePlease check the document version of this publication:• A submitted manuscript is the version of the article upon submission and before peer-review. There canbe important differences between the submitted version and the official published version of record.People interested in the research are advised to contact the author for the final version of the publication,or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and pagenumbers.Link to publicationGeneral rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyrightowners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with theserights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain• You may freely distribute the URL identifying the publication in the public portal.If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license above,please follow below link for the End User Agreement:www.umlib.nl/taverne-licenseTake down policyIf you believe that this document breaches copyright please contact us at:repository@maastrichtuniversity.nlproviding details and we will investigate your claim.Download date: 04 Jan. 2021Journal of Huntington’s Disease 8 (2019) 361–362DOI 10.3233/JHD-199004IOS Press361Letter to the EditorReply to Oliver W Quarrell et al.:“Letter in response to Tibben et al.,Risk Assessment for Huntington’sDisease for (Future) Offspring RequiresOffering Preconceptional CAG Analysisto Both Partners”Aad Tibbena,∗, Wybo J. Dondorpb, Guido M. de Wertb, Christine E. de Die-Smuldersc,Moniek Losekoota and Emilia K. BijlsmaaaDepartment of Clinical Genetics, Leiden University Medical Center, Leiden, The NetherlandsbDepartment of Health, Ethics and Society, Maastricht University, Maastricht, The NetherlandscDepartment of Clinical Genetics, Maastricht University Medical Centre, Maastricht, The NetherlandsDear Editor,We are grateful to Quarell and others for theirresponse [1] to our article [2], and for the opportunityto respond. The authors feel that the case for alteringthe current guidelines for predictive testing for Hunt-ington’s disease [3] has not yet been made becauseof insufficient information about the behaviour ofintermediate alleles (IA), reduced penetrance alleles(RPA), and fully penetrant alleles (FPA) in familiesnot yet identified as Huntington families. We agreewith the authors that more knowledge of and insightinto the dynamics of the alleles is needed to justifychanging the guidelines. However, we want to meetthe concerns of couples who wish to have offspringbut feel the responsibility for preventing the concep-tion or birth of a child with an HD allele. One of themain reasons of individuals at risk to request predic-∗Correspondence to: Aad Tibben, PhD, Leiden UniversityMedical Center, Department of Clinical Genetics, P.O Box 9600,2300 RC Leiden, The Netherlands. Tel.: +31 71 526 8033; Fax:+31 71 526 6794; E-mail: a.tibben@lumc.nl.tive testing is the wish to have children. Until now,tested individuals expect that either test result allowsthem to exclude HD in their offspring, in case of aunfavourable test result by opting for prenatal (PND)or preimplantation genetic testing (PGT). The aim ofgenetic counseling, in general [4] and according to theguidelines [3], is to give individuals at risk, who wishto take the predictive test, up to date, relevant informa-tion in order to make an informed voluntary decision.Moreover, couples opting for prenatal testing shouldbe made fully aware of all possible outcomes andconsequences of prenatal testing [3].The question of an identified non-carrier, whetherthe chance of Huntington in his or her offspring isexcluded, cannot be confirmed because of the - albeitvery small - chance of an expanded repeat in the non-HD partner. Similarly, a carrier and his or her partner,opting for PND or PGT, need to be informed thatprenatal testing might reveal a small chance that anexpanded repeat will be found in the non-HD partner.Consequently, couples deserve to be well informedand counseled so that they can make a decision thatdoes justice to their reproductive concerns.ISSN 1879-6397/19/$35.00 © 2019 – IOS Press and the authors. All rights reserved362 A. Tibben et al. / Letter to the EditorThe authors compare our case with chromosomemicroarray analyses in the context of PND that mightelicit some copy number variants that may predis-pose to developmental disability or neuropsychiatricillness. Moreover, their comparison with expandedcarrier screening for cystic fibrosis, spinal muscularatrophy or fragile X concerns decisions in the contextof population screening, which makes this analogyinvalid.Quarell c.s. seem to assume that we propose to rou-tinely test the non-HD partners - which they wouldnot prefer. We definitely agree on the latter as rou-tine testing is not our point. We argue that this testshould be an option in counseling couples in thisspecific situation. We acknowledge the concerns anduncertainties surrounding this additional testing, butthat is no reason not to discuss this testing opportu-nity with couples who might want to use it becauseof their specific request for help, c.q. prevention ofHuntington’s disease in offspring. Whether counsel-ing is offered from a non-directive counseling modelor a shared decision-making model, in our opinioncouples need to be fully informed. But given theuncertainties and complexities of the alleles in ques-tion, we do think that discussing and possibly offeringan additional test for non-HD partners should takeplace in a research setting to investigate what soundcounseling entails in this context.Aad Tibben, PhDWybo J. Dondorp, PhDGuido M. de Wert, PhDChristine E. de Die-Smulders, MD, PhDMoniek Losekoot, PhDEmilia K. Bijlsma MD, PhDREFERENCES[1] Quarrell O, Delatycki MB, Clarke A, et al. Letter in responseto Tibben et al Risk assessment for Huntington’s Diseasefor (future) offspring requires offering preconceptual CAGanalysis to both partners. J Huntingtons Dis. 2019.[2] Tibben A, Dondorp WJ, de Wert GM, de Die-Smulders CE,Losekoot M, Bijlsma EK. Risk Assessment for Huntington’sDisease for (Future) Offspring Requires Offering Preconcep-tional CAG Analysis to Both Partners. J Huntingtons Dis.2019;8(1):71-8.[3] MacLeod R, Tibben A, Frontali M, et al. Recommendationsfor the predictive genetic test in Huntington’s disease. ClinGenet. 2013;83(3):221-31.[4] Fraser FC. Genetic counseling. Am J Hum Genet. 1974;26(5):636-59.

Reply to Oliver W Quarrell et al.:"Letter in response to Tibben et al., Risk Assessment for Huntington's Disease for (Future) Offspring Requires Offering Preconceptional CAG Analysis to Both Partners"

   Reply to Oliver W Quarrell et al.Citation for published version (APA):Tibben, A., Dondorp, W. J., de Wert, G. M., de Die-Smulders, C. E., Losekoot, M., & Bijlsma, E. K. (2019).Reply to Oliver W Quarrell et al. "Letter in response to Tibben et al., Risk Assessment for Huntington'sDisease for (Future) Offspring Requires Offering Preconceptional CAG Analysis to Both Partners". Journalof Huntington's disease, 8(3), 361-362. https://doi.org/10.3233/jhd-199004Document status and date:Published: 01/01/2019DOI:10.3233/jhd-199004Document Version:Publisher's PDF, also known as Version of recordDocument license:TavernePlease check the document version of this publication:• A submitted manuscript is the version of the article upon submission and before peer-review. There canbe important differences between the submitted version and the official published version of record.People interested in the research are advised to contact the author for the final version of the publication,or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and pagenumbers.Link to publicationGeneral rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyrightowners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with theserights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain• You may freely distribute the URL identifying the publication in the public portal.If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license above,please follow below link for the End User Agreement:www.umlib.nl/taverne-licenseTake down policyIf you believe that this document breaches copyright please contact us at:repository@maastrichtuniversity.nlproviding details and we will investigate your claim.Download date: 01 Oct. 2023Journal of Huntington’s Disease 8 (2019) 361–362DOI 10.3233/JHD-199004IOS Press361Letter to the EditorReply to Oliver W Quarrell et al.:“Letter in response to Tibben et al.,Risk Assessment for Huntington’sDisease for (Future) Offspring RequiresOffering Preconceptional CAG Analysisto Both Partners”Aad Tibbena,∗, Wybo J. Dondorpb, Guido M. de Wertb, Christine E. de Die-Smuldersc,Moniek Losekoota and Emilia K. BijlsmaaaDepartment of Clinical Genetics, Leiden University Medical Center, Leiden, The NetherlandsbDepartment of Health, Ethics and Society, Maastricht University, Maastricht, The NetherlandscDepartment of Clinical Genetics, Maastricht University Medical Centre, Maastricht, The NetherlandsDear Editor,We are grateful to Quarell and others for theirresponse [1] to our article [2], and for the opportunityto respond. The authors feel that the case for alteringthe current guidelines for predictive testing for Hunt-ington’s disease [3] has not yet been made becauseof insufficient information about the behaviour ofintermediate alleles (IA), reduced penetrance alleles(RPA), and fully penetrant alleles (FPA) in familiesnot yet identified as Huntington families. We agreewith the authors that more knowledge of and insightinto the dynamics of the alleles is needed to justifychanging the guidelines. However, we want to meetthe concerns of couples who wish to have offspringbut feel the responsibility for preventing the concep-tion or birth of a child with an HD allele. One of themain reasons of individuals at risk to request predic-∗Correspondence to: Aad Tibben, PhD, Leiden UniversityMedical Center, Department of Clinical Genetics, P.O Box 9600,2300 RC Leiden, The Netherlands. Tel.: +31 71 526 8033; Fax:+31 71 526 6794; E-mail: a.tibben@lumc.nl.tive testing is the wish to have children. Until now,tested individuals expect that either test result allowsthem to exclude HD in their offspring, in case of aunfavourable test result by opting for prenatal (PND)or preimplantation genetic testing (PGT). The aim ofgenetic counseling, in general [4] and according to theguidelines [3], is to give individuals at risk, who wishto take the predictive test, up to date, relevant informa-tion in order to make an informed voluntary decision.Moreover, couples opting for prenatal testing shouldbe made fully aware of all possible outcomes andconsequences of prenatal testing [3].The question of an identified non-carrier, whetherthe chance of Huntington in his or her offspring isexcluded, cannot be confirmed because of the - albeitvery small - chance of an expanded repeat in the non-HD partner. Similarly, a carrier and his or her partner,opting for PND or PGT, need to be informed thatprenatal testing might reveal a small chance that anexpanded repeat will be found in the non-HD partner.Consequently, couples deserve to be well informedand counseled so that they can make a decision thatdoes justice to their reproductive concerns.ISSN 1879-6397/19/$35.00 © 2019 – IOS Press and the authors. All rights reserved362 A. Tibben et al. / Letter to the EditorThe authors compare our case with chromosomemicroarray analyses in the context of PND that mightelicit some copy number variants that may predis-pose to developmental disability or neuropsychiatricillness. Moreover, their comparison with expandedcarrier screening for cystic fibrosis, spinal muscularatrophy or fragile X concerns decisions in the contextof population screening, which makes this analogyinvalid.Quarell c.s. seem to assume that we propose to rou-tinely test the non-HD partners - which they wouldnot prefer. We definitely agree on the latter as rou-tine testing is not our point. We argue that this testshould be an option in counseling couples in thisspecific situation. We acknowledge the concerns anduncertainties surrounding this additional testing, butthat is no reason not to discuss this testing opportu-nity with couples who might want to use it becauseof their specific request for help, c.q. prevention ofHuntington’s disease in offspring. Whether counsel-ing is offered from a non-directive counseling modelor a shared decision-making model, in our opinioncouples need to be fully informed. But given theuncertainties and complexities of the alleles in ques-tion, we do think that discussing and possibly offeringan additional test for non-HD partners should takeplace in a research setting to investigate what soundcounseling entails in this context.Aad Tibben, PhDWybo J. Dondorp, PhDGuido M. de Wert, PhDChristine E. de Die-Smulders, MD, PhDMoniek Losekoot, PhDEmilia K. Bijlsma MD, PhDREFERENCES[1] Quarrell O, Delatycki MB, Clarke A, et al. Letter in responseto Tibben et al Risk assessment for Huntington’s Diseasefor (future) offspring requires offering preconceptual CAGanalysis to both partners. J Huntingtons Dis. 2019.[2] Tibben A, Dondorp WJ, de Wert GM, de Die-Smulders CE,Losekoot M, Bijlsma EK. Risk Assessment for Huntington’sDisease for (Future) Offspring Requires Offering Preconcep-tional CAG Analysis to Both Partners. J Huntingtons Dis.2019;8(1):71-8.[3] MacLeod R, Tibben A, Frontali M, et al. Recommendationsfor the predictive genetic test in Huntington’s disease. ClinGenet. 2013;83(3):221-31.[4] Fraser FC. Genetic counseling. Am J Hum Genet. 1974;26(5):636-59.

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Reply to Oliver W Quarrell et al.:"Letter in response to Tibben et al., Risk Assessment for Huntington's Disease for (Future) Offspring Requires Offering Preconceptional CAG Analysis to Both Partners"

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