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Review
. 2024 Jul;194(7):e63531.
doi: 10.1002/ajmg.a.63531. Epub 2024 Feb 29.

3q29 duplications: A cohort of 46 patients and a literature review

Marie Massier  1 , Martine Doco-Fenzy  1   2 , Matthieu Egloff  3   4 , Xavier Le Guillou  3   5 , Gwenaël Le Guyader  3 , Sylvia Redon  6   7   8 , Caroline Benech  8 , Karine Le Millier  6 , Kevin Uguen  6   7   8 , Juliette Ropars  7 , Elise Sacaze  7 , Séverine Audebert-Bellanger  6   7 , Andreea Apetrei  9 , Arnaud Molin  9 , Nicolas Gruchy  9 , Aline Vincent-Devulder  9 , Marta Spodenkiewicz  10 , Clémence Jacquin  1 , Gauthier Loron  11 , Marie Thibaud  12 , Geoffroy Delplancq  13 , Sophie Brisset  13 , Marion Lesieur-Sebellin  14 , Valérie Malan  14 , Serge Romana  14 , Marlène Rio  14 , Sandrine Marlin  14 , Jeanne Amiel  14 , Valentine Marquet  15 , Benjamin Dauriat  15 , Kamran Moradkhani  2 , Sandra Mercier  2 , Bertrand Isidor  2 , Stéphanie Arpin  16 , Mathilde Pujalte  17 , Guillaume Jedraszak  18 , Céline Pebrel-Richard  19 , Gaëlle Salaun  19 , Fanny Laffargue  20 , John Boudjarane  21 , Chantal Missirian  21 , Nora Chelloug  22 , Annick Toutain  16 , Jean Chiesa  23 , Boris Keren  24 , Cyril Mignot  24 , Evan Gouy  17 , Sylvie Jaillard  25 , Emilie Landais  1 , Céline Poirsier  1
Affiliations
Free article
Review

3q29 duplications: A cohort of 46 patients and a literature review

Marie Massier et al. Am J Med Genet A. 2024 Jul.
Free article

Abstract

Duplications of the 3q29 cytoband are rare chromosomal copy number variations (CNVs) (overlapping or recurrent ~1.6 Mb 3q29 duplications). They have been associated with highly variable neurodevelopmental disorders (NDDs) with various associated features or reported as a susceptibility factor to the development of learning disabilities and neuropsychiatric disorders. The smallest region of overlap and the phenotype of 3q29 duplications remain uncertain. We here report a French cohort of 31 families with a 3q29 duplication identified by chromosomal microarray analysis (CMA), including 14 recurrent 1.6 Mb duplications, eight overlapping duplications (>1 Mb), and nine small duplications (<1 Mb). Additional genetic findings that may be involved in the phenotype were identified in 11 patients. Focusing on apparently isolated 3q29 duplications, patients present mainly mild NDD as suggested by a high rate of learning disabilities in contrast to a low proportion of patients with intellectual disabilities. Although some are de novo, most of the 3q29 duplications are inherited from a parent with a similar mild phenotype. Besides, the study of small 3q29 duplications does not provide evidence for any critical region. Our data suggest that the overlapping and recurrent 3q29 duplications seem to lead to mild NDD and that a severe or syndromic clinical presentation should warrant further genetic analyses.

Keywords: 3q29 duplication; chromosomal microarray analysis; copy number variation; genomic disorder; multiple molecular diagnoses; neurodevelopmental disorders.

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References

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