Clinical features and gene mutation analysis of a male case of subcortical band heterotopia caused by mosaic mutation of DCX gene / 中华神经科杂志

Objective:To investigate the clinical phenotype and genotype of a male case of subcortical band heterotopia caused by mosaic mutation of DCX gene.Methods:The clinical data and magnetic resonance imaging (MRI) features of a male case of subcortical band heterotopia diagnosed in the Department of Neurology, Children′s Hospital Affiliated to Zhengzhou University in August 2020 were analyzed retrospectively. At the same time, the whole exon sequencing of the families was performed by next generation sequencing method, the suspicious mutation was verified by polymerase chain reaction Sanger sequencing, and their genetic mutation characteristics were analyzed.Results:The proband, one male, aged 5 years and 1 month, was hospitalized in August 2020 with the complaint of intermittent convulsions for 4 years and six months. Clinical features included that limb muscle tension was slightly high, intellectual and motor development was backward, and head circumference was 48 cm. MRI of his head showed diffuse thick subcortical band heterotopia. The detection of whole exon sequencing in his family showed that there was hemizygous mosaic mutation in DCX gene (mosaic ratio 44%), c.148A>G (p.k50E). The mosaic ratios of oral mucosa and urinalysis were 38.2% and 44.8% respectively. His parents were wild-type, The mutation found in this patient has not been reported at home and abroad.Conclusions:The mosaic variation of DCX gene can cause subcortical band heterotopia in males. The variation of DCX gene c.148A>G (p.k50E) may be the possible cause of the proband, which expands the variation spectrum of subcortical band heterotopia.

Lissencephaly child showing FISH negative and mutation in DCX gene with normal parental genetic makeup.

Lissencephaly is a clinically and genetically heterogeneous malformation of the brain, leading to a severe disabling condition and seizures. The recent discovery of molecular techniques and identification of lissencephaly genes (LIS 1 and DCX) has allowed etiologic diagnosis of this disorder. We describe a patient with lissencephaly in whom fluorescence in situ hybridization and DCX mutation analysis determined etiologic diagnosis, allowing precise genetic counseling and providing prenatal diagnosis for the family.