Clinical delineation, sex differences, and genotype–phenotype correlation in pathogenic KDM6A variants causing X-linked Kabuki syndrome type 2

Víctor Faundes, Stephanie Goh, Rhoda Akilapa, Heidre Bezuidenhout, Hans T. Bjornsson, Lisa Bradley, Angela F. Brady, Elise Brischoux-Boucher, Han Brunner, Saskia Bulk, Natalie Canham, Declan Cody, Maria Lisa Dentici, Maria Cristina Digilio, Frances Elmslie, Andrew E. Fry, Harinder Gill, Jane Hurst, Diana Johnson, Sophie JuliaKatherine Lachlan, Robert Roger Lebel, Melissa Byler, Eric Gershon, Edmond Lemire, Maria Gnazzo, Francesca Romana Lepri, Antonia Marchese, Meriel McEntagart, Julie McGaughran, Seiji Mizuno, Nobuhiko Okamoto, Claudine Rieubland, Jonathan Rodgers, Erina Sasaki, Emmanuel Scalais, Ingrid Scurr, Mohnish Suri, Ineke van der Burgt, Naomichi Matsumoto, Noriko Miyake, Valérie Benoit, Damien Lederer, Siddharth Banka

Research output: Contribution to journalArticlepeer-review


Purpose: The variant spectrum and the phenotype of X-linked Kabuki syndrome type 2 (KS2) are poorly understood. Methods: Genetic and clinical details of new and published individuals with pathogenic KDM6A variants were compiled and analyzed. Results: Sixty-one distinct pathogenic KDM6A variants (50 truncating, 11 missense) from 80 patients (34 males, 46 females) were identified. Missense variants clustered in the TRP 2, 3, 7 and Jmj-C domains. Truncating variants were significantly more likely to be de novo. Thirteen individuals had maternally inherited variants and one had a paternally inherited variant. Neonatal feeding difficulties, hypoglycemia, postnatal growth retardation, poor weight gain, motor delay, intellectual disability (ID), microcephaly, congenital heart anomalies, palate defects, renal malformations, strabismus, hearing loss, recurrent infections, hyperinsulinism, seizures, joint hypermobility, and gastroesophageal reflux were frequent clinical findings. Facial features of over a third of patients were not typical for KS. Males were significantly more likely to be born prematurely, have shorter stature, and severe developmental delay/ID. Conclusion: We expand the KDM6A variant spectrum and delineate the KS2 phenotype. We demonstrate that the variability of the KS2 phenotypic depends on sex and the variant type. We also highlight the overlaps and differences between the phenotypes of KS2 and KS1.

Original languageEnglish (US)
Pages (from-to)1202-1210
Number of pages9
JournalGenetics in Medicine
Issue number7
StatePublished - Jul 2021

ASJC Scopus subject areas

  • Genetics(clinical)


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