Background Koolen-de Vries syndrome (KdVS) is a multisystem neurodevelopmental disorder caused by 17q21.31 deletions or mutations in KANSL1. It was mainly described in children.
Methods A retrospective study on 9 subjects aged 19–45 years and revision of 18 literature patients, with the purpose to get insights into the phenotypic evolution with time, and into the clinical manifestations in adulthood.
Results Seven patients had a 17q21.31 deletion and two a point mutation in KANSL1. All had intellectual disability, which was mild in five (56%) and moderate in four (44%). Epilepsy was diagnosed in four subjects (44%), with onset from 1 to 7 years and full remission before 9 years in 3/4 patients. Scoliosis affected seven individuals (77.7%) and it was substantially stable with age in 5/7 patients, allowing for simple daily activities. Two subjects had severely progressive scoliosis, which was surgically corrected. Overweight or true obesity did occur after puberty in six patients (67%). Behaviour abnormalities were recorded in six patients (67%). The facial phenotype slightly evolved with time to include thick eyebrows, elongated nose and pronounced pointed chin. Despite behaviour abnormalities, happy disposition and sociable attitudes were common. Half of patients had fluent language and were good at writing and reading. Rich language, although limited to single words or short sentences, and very limited or absent skills in writing and reading were observed in the remaining patients. Autonomy in daily activities and personal care was usually limited.
Conclusions Distinctive features in adult KdVS subjects include intellectual disability, overweight/obesity, behaviour abnormalities with preserved social interest, ability in language, slight worsening of the facial phenotype and no seizures.
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SA and SF contributed equally.
Correction notice This article has been corrected since it was published Online First. The affiliation of authors Simona Amenta, Silvia Frangella, Giuseppe Marangi, Serena Lattante, Stefania Ricciardi, and Paolo Nicolò Doronzio has been corrected. Also, Simona Amenta and Silvia Frangella contributed equally, and table 2 has been amended.
Contributors MZ planned the study, analysed clinical data, administered the questionnaire and wrote the manuscript. SA contributed to the writing of the MS, to the administering of the questionnaire and performed literature revision. SF, DO, SL, SR and PND performed genomic analyses and evaluation of genomic database and contributed to comparative evaluation of the genetic and the clinical data. CV and IC performed neurological evaluation and revision of brain MRI. GZ, MG, ES and CG contributed to the clinical evaluation and participated in patients’ recruitment. GM participated in writing the manuscript and in literature revision.
Funding This work was supported by a MIUR-University Grant D3.2, 2017; by Associazione Kool Kids Kansl1 Italia and by Fondazione Cassa di Risparmio di Lucca.
Competing interests None declared.
Patient consent for publication Parental/guardian consent obtained.
Ethics approval Institutional review board of DIPUSVSP, Protocol number 26-05-2080, Università Cattolica Sacro Cuore, Roma, Italy.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement All data relevant to the study are included in the article or uploaded as supplementary information. Our data are not stored in a repository. They are all included in the article.
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