Clonazepam as an Effective Treatment for Epilepsy in a Female Patient with <b><i>NEXMIF</i></b> Mutation: Case Report

Abstract

The &lt;i&gt;NEXMIF&lt;/i&gt; (&lt;i&gt;KIAA2022&lt;/i&gt;) gene is located in the X chromosome, and hemizygous mutations in &lt;i&gt;NEXMIF&lt;/i&gt; cause X-linked intellectual disability in male patients. Female patients with heterozygous mutations in &lt;i&gt;NEXMIF&lt;/i&gt; also show similar, but milder, intellectual disability. Most female patients demonstrate intractable epilepsy compared with male patients, and the treatment strategy for epilepsy is still uncertain. Thus far, 24 female patients with &lt;i&gt;NEXMIF&lt;/i&gt; mutations have been reported. Of these 24 patients, 20 also have epilepsy. Until now, epilepsy has been controlled in only 2 of these female patients. We report a female patient with a heterozygous de novo mutation, NM_001008537.2:c.1123del (p.Glu375Argfs*21), in &lt;i&gt;NEXMIF&lt;/i&gt;. The patient showed mild intellectual disability, facial dysmorphism, obesity, generalized tonic-clonic seizures, and nonconvulsive status epilepticus. Sodium valproate was effective but caused secondary amenorrhea. We successfully treated her epilepsy with clonazepam without side effects, indicating that clonazepam might be a good choice to treat epilepsy in patients with &lt;i&gt;NEXMIF&lt;/i&gt; mutations.