Brain MR images depicting periventricular nodular heterotopia distributions in a cohort of 7 unrelated individuals with ZTTK syndrome. A, Axial T1-weighted MRI of the brain of individual 1 at 7 years 7 months of age revealing sparse bilateral frontal heterotopia (white arrowheads). B, Axial T1-weighted MRI of the brain of individual 2 at 11 years and 6 months of age revealing sparse right unilateral frontal and midbody heterotopia (white arrowheads). C, Axial T2-weighted MRI of the brain of individual 3 at 1 year of age revealing sparse bilateral frontal horn heterotopia (white arrowheads). D, Axial T2-weighted MRI of the brain of individual 4 at 1 year 4 months of age revealing sparse bilateral frontal horn heterotopia (white arrowheads). E, Axial T1-weighted MRI of the brain of individual 5 at 1 year 8 months of age revealing a heterotopion of the right frontal horn (white arrowhead). F, Right parasagittal T1-weighted MRI of the brain of individual 6 at 15 years 2 months of age revealing a heterotopion of the right frontal horn (white arrowhead). G, Left parasagittal T1-weighted MRI of the brain of individual 7 at 1 year 2 months of age revealing sparse left frontal horn heterotopia (white arrowheads).