WDR45 mutations in three male patients with West syndrome

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Abstract

West syndrome is an early-onset epileptic encephalopathy characterized by clustered spasms with hypsarrhythmia seen on electroencephalogram (EEG). West syndrome is genetically heterogeneous, and its genetic causes have not been fully elucidated. WD Repeat Domain 45 (WDR45) resides on Xp11.23, and encodes a member of the WD repeat protein interacting with phosphoinositides (WIPI) family, which is crucial in the macroautophagy pathway. De novo mutations in WDR45 cause beta-propeller protein-associated neurodegeneration characterized by iron accumulation in the basal ganglia. In this study, we performed whole exome sequencing of individuals with West syndrome and identified three WDR45 mutations in three independent males (patients 1, 2 and 3). Two novel mutations occurred de novo (patients 1 and 2) and the remaining mutation detected in a male patient (patient 3) and his affected sister was inherited from the mother, harboring the somatic mutation. The three male patients showed early-onset intractable seizures, profound intellectual disability and developmental delay. Their brain magnetic resonance imaging scans showed cerebral atrophy. We found no evidence of somatic mosaicism in the three male patients. Our findings indicate that hemizygous WDR45 mutations in males lead to severe epileptic encephalopathy.

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Acknowledgements

We express our heartfelt gratitude to all the patients and their families for participating in this study. We would like to thank Ms N Watanabe, M Sato and K Takabe for their excellent technical assistance. We also thank Mr D Yamaguchi for his assistance with the bioinformatics analysis. This work was supported in part by a grant for Research on Measures for Intractable Diseases, a grant for Comprehensive Research on Disability Health and Welfare, the Strategic Research Program for Brain Science (SRPBS) and a grant for Initiative on Rare and Undiagnosed Diseases in Pediatrics (IRUD-P) from Japan Agency for Medical Research and Development (AMED); a Grant-in-Aid for Scientific Research on Innovative Areas (Transcription Cycle) from the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT); Grants-in-Aid for Scientific Research (A, B and C), and challenging Exploratory Research from the Japan Society for the Promotion of Science (JSPS); the fund for Creation of Innovation Centers for Advanced Interdisciplinary Research Areas Program in the Project for Developing Innovation Systems from the Japan Science and Technology Agency (JST); the Takeda Science Foundation; the Yokohama Foundation for Advancement of Medical Science; and the Hayashi Memorial Foundation for Female Natural Scientists.

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Correspondence to Naomichi Matsumoto.

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