Report of a case of grey matter heterotopia combined with epilepsy due to TUBB2B gene variant and review of literature / 中华神经科杂志

ABSTRACT

Objective:To report the clinical phenotype and mutation site of a patient with grey matter heterotopia caused by a de novo heterozygous missense mutation in the TUBB2B gene, and to expand the phenotypic and mutational spectrum of TUBB2B mutations. Methods:One patient with TUBB2B mutation who presented to the Department of Neurology, the First Affiliated Hospital of Air Force Medical University in July 2017 was collected and analyzed for clinical features and mutation site, and a review of previous studies was performed. Results:The male patient started at the age of 18 and presented mainly with seizures, poor left-handed fine motor skills and poor spatial imagination. Magnetic resonance imaging showed nodular grey matter heterotopia in the right cerebral hemisphere, right frontoparietal-temporal localized cerebral gyrus, and cerebral sulcus shallow flat.The whole exon gene test suggested a heterozygous missense mutation in the TUBB2B gene c.776 C>T (p.Pro259Leu), which was wild-type in both of his parents. The mutation site was located between the tubulin and tubulin-c structural domains and did not affect the function of the essential structural domain. After treatment with magnesium valproate in combination with levetiracetam, the patient′s seizure symptoms were significantly controlled and he has been seizure-free for 3 years now. Conclusions:The TUBB2B gene c.776 C>T (p.Pro259Leu) heterozygous missense mutation is a novel missense mutation causing grey matter heterotopia. The patient had a good prognosis, and the combination of two antiepileptic drugs resulted in complete seizure control.