NEXMIF Combined with KIDINS220 Gene Mutation Caused Neurodevelopmental Disorder and Epilepsy: One Case Report.

of Medical History: A male infant, 8 months old, was admitted to hospital with cough and fever. The clinical symptoms were found to be mental retardation, obesity, dystonia, movement limitation, and visual retardation. Early development was normal, but after 6 months, the child developed upright head instability, difficulty grasping, and seizures. Symptoms and Signs: The child presents with mental retardation, obesity, increased muscle tone, motor dysfunction, visual impairment, and seizures.

Diagnosis: A whole exon test was performed to detect a neurite extension and migration factor (NEXMIF) gene mutation (NM_001008537.2: c.1042C > T (p. Arg348*)), which is known to be associated with intellectual disability and neurological symptoms. In addition, the test revealed a mutation in the Kinase D interacting substrate of 220 kDa (KIDINS220) gene (NM_020738.2: c.3242_3243insC (p. Leu1082AIafs*5)) with a heterozygous mutation in the father and wild type in the mother.

Treatment: The patient was treated with anti-infection, aerosol inhalation, calcium supplement, and anti-epileptic drugs (levetiracetam), and the disease was controlled. Home and hospital rehabilitation is also underway.

Clinical outcome: The condition of the child improved after treatment and no seizures occurred again. The patient needs continuous rehabilitation treatment and follow-up observation.

Conclusion: For male children with unexplained neurodevelopmental disorders and comorbidities such as obesity, dystonia, and seizures, mutations in related genes such as NEXMIF should be considered. Clinical practice should improve genetic testing as early as possible to provide a basis for genetic counseling.