Rare variants in the genetic background modulate cognitive and developmental phenotypes in individuals carrying disease-associated variants

Lucilla Pizzo, Matthew Jensen, Andrew Polyak, Jill A. Rosenfeld, Katrin Mannik, Arjun Krishnan, Elizabeth McCready, Olivier Pichon, Cedric Le Caignec, Anke Van Dijck, Kate Pope, Els Voorhoeve, Jieun Yoon, Paweł Stankiewicz, Sau Wai Cheung, Damian Pazuchanics, Emily Huber, Vijay Kumar, Rachel L. Kember, Francesca MariAurora Curró, Lucia Castiglia, Ornella Galesi, Emanuela Avola, Teresa Mattina, Marco Fichera, Luana Mandarà, Marie Vincent, Mathilde Nizon, Sandra Mercier, Claire Bénéteau, Sophie Blesson, Dominique Martin-Coignard, Anne Laure Mosca-Boidron, Jean Hubert Caberg, Maja Bucan, Susan Zeesman, Małgorzata J.M. Nowaczyk, Mathilde Lefebvre, Laurence Faivre, Patrick Callier, Cindy Skinner, Boris Keren, Charles Perrine, Paolo Prontera, Nathalie Marle, Alessandra Renieri, Alexandre Reymond, R. Frank Kooy, Bertrand Isidor, Charles Schwartz, Corrado Romano, Erik Sistermans, David J. Amor, Joris Andrieux, Santhosh Girirajan*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Purpose: To assess the contribution of rare variants in the genetic background toward variability of neurodevelopmental phenotypes in individuals with rare copy-number variants (CNVs) and gene-disruptive variants. Methods: We analyzed quantitative clinical information, exome sequencing, and microarray data from 757 probands and 233 parents and siblings who carry disease-associated variants. Results: The number of rare likely deleterious variants in functionally intolerant genes (“other hits”) correlated with expression of neurodevelopmental phenotypes in probands with 16p12.1 deletion (n=23, p=0.004) and in autism probands carrying gene-disruptive variants (n=184, p=0.03) compared with their carrier family members. Probands with 16p12.1 deletion and a strong family history presented more severe clinical features (p=0.04) and higher burden of other hits compared with those with mild/no family history (p=0.001). The number of other hits also correlated with severity of cognitive impairment in probands carrying pathogenic CNVs (n=53) or de novo pathogenic variants in disease genes (n=290), and negatively correlated with head size among 80 probands with 16p11.2 deletion. These co-occurring hits involved known disease-associated genes such as SETD5, AUTS2, and NRXN1, and were enriched for cellular and developmental processes. Conclusion: Accurate genetic diagnosis of complex disorders will require complete evaluation of the genetic background even after a candidate disease-associated variant is identified.

Original languageEnglish
Pages (from-to)816-825
Number of pages10
JournalGenetics in Medicine
Volume21
Issue number4
DOIs
Publication statusPublished - 1 Apr 2019

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