Mosaic DCX deletion causes subcortical band heterotopia in males

Subcortical band heterotopia (SBH) is a neuronal migration disorder usually described in females carrying heterozygous mutations in the X-linked doublecortin (DCX) gene. Hemizygous DCX mutations in males result in lissencephaly. Recently, exonic deletions of DCX resulting in a severer form of agyria have been reported. Nevertheless, rare male patients with SBH have been described with somatic mosaicism of point mutations. Here, we identified a somatic mosaicism for a deletion of exon 4 in the DCX gene in a male patient with SBH detected prenatally. This finding points to the possible implication of mosaic deletions in the DCX gene in unexplained forms of SBH and may allow for detection of SBH prenatally.