Clinical and genetic analysis of a child with West syndrome due to a de novo variant of NEXMIF gene

Abstract

To investigate the clinical features and genetic variant of a child with West syndrome due to a variant of NEXMIF gene. A child who was admitted to the First Medical Center of Chinese PLA General Hospital in March 2021 was selected as the study subject. Clinical data of the patient was collected. The child and his parents were subjected to whole exome sequencing. Candidate variant was verified by Sanger sequencing and pathogenicity analysis. The child, a 4-month-old boy, had presented with spastic seizures with no obvious cause. Abnormal EEG, severe hypsarrhythmia, and multiple spastic seizures were discovered. Cranial MRI revealed widening of the extracerebral space at the top of the frontal lobe. Physical examination revealed that the child could not hold his head up, and could not respond to sounds or follow objects with his eyes. He also has microcephaly, with height < 1 s. The child was diagnosed with West syndrome at a local hospital, and was given prednisone orally for 3 months, with seizures under control. Topiramate tablets were taken orally for maintenance treatment, and he has been seizure-free for 7 months. DNA sequencing revealed that he has harbored a de novo nonsense variant of c.982_c.983delTT (p.L328Dfs*23) in the NEXMIF gene. For children with West syndrome with severe developmental delay or even regression as the first symptoms, uncontrollable seizures and abnormal facial appearance, mutations of the NEXMIF gene should be suspected, and genetic testing can facilitate early diagnosis and treatment.