1. EHMT1 mosaicism in apparently unaffected parents is associated with autism spectrum disorder and neurocognitive dysfunction.
- Author
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de Boer A, Vermeulen K, Egger JIM, Janzing JGE, de Leeuw N, Veenstra-Knol HE, den Hollander NS, van Bokhoven H, Staal W, and Kleefstra T
- Subjects
- Adult, Asymptomatic Diseases, Autism Spectrum Disorder diagnosis, Cognitive Dysfunction diagnosis, Female, Germ-Line Mutation, Heterozygote, Humans, Male, Mood Disorders diagnosis, Parents, Autism Spectrum Disorder genetics, Cognitive Dysfunction genetics, Histone-Lysine N-Methyltransferase genetics, Mood Disorders genetics, Mosaicism
- Abstract
Background: Genetic mosaicism is only detected occasionally when there are no obvious health or developmental issues. Most cases concern healthy parents in whom mosaicism is identified upon targeted testing of a genetic defect that was initially detected in their children. A germline genetic defect affecting the euchromatin histone methyltransferase 1 ( EHMT1 ) gene causes Kleefstra syndrome, which is associated with the typical triad of distinct facial appearance, (childhood) hypotonia, and intellectual disability. A high degree of psychopathology is associated with this syndrome. A few parents with a mosaic EHMT1 mutation have been detected upon testing after a child was diagnosed with a germline EHMT1 defect. At first glance, carriers of a mosaic EHMT1 mutation appeared to function normally. However, recent studies have shown that de novo, postzygotic mutations in important developmental genes significantly contribute to autism spectrum disorder (ASD). Therefore, we hypothesized that EHMT1 mosaicism could cause neuropsychiatric defects. To investigate this, we performed a detailed investigation of cognitive neuropsychiatric parameters in parents identified with EHMT1 mosaicism., Methods: Three adults (two males, one female) with a genetically confirmed diagnosis of EHMT1 mosaicism were examined by means of a battery of tests and observational instruments covering both neurocognitive and psychiatric features. The battery included the following instruments: the Autism Diagnostic Observation Schedule (ADOS), the mini Psychiatric Assessment Schedules for Adults with Developmental Disabilities (mini PAS-ADD), the Vineland Adaptive Behavior Scales (VABS), and the Cambridge Neuropsychological Test Automated Battery (CANTAB). These measures were compared with our previously reported data from Kleefstra syndrome patients with confirmed (germline) EHMT1 defects., Results: All three subjects achieved maximum total scores on the VABS, indicative of adequate (adaptive) functioning. In all, scores above cutoff were found on the ADOS for ASD and on the mini PAS-ADD for major depressive disorder (lifetime). Finally, results on the CANTAB showed impaired cognitive flexibility in all subjects., Conclusion: Individuals with EHMT1 mosaicism seem to have increased vulnerability for developing severe psychopathology, especially ASD and mood disorders. Although at first glance they appear to be well-adapted in their daily functioning, they may experience significant psychiatric symptoms and show reduced cognitive flexibility in comparison to the general population., Competing Interests: The regional medical ethical committee (medical research ethics committee CMO/METC Arnhem-Nijmegen, the Netherlands) approved the study (NL43187.091.13), which was performed in full accordance with the Declaration of Helsinki. Informed consent was obtained.Written informed consent was obtained from the subjects for publication of their individual details in this manuscript. The consent form is held by the authors and is available for review by the Editor-in-Chief.The authors declare that they have no competing interests.Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
- Published
- 2018
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