Disorders of Microtubule Function in Neurons: Imaging Correlates

A 7-week-old infant with a TUBB2B mutation. Midline sagittal T1WI (A) shows a short, thin corpus callosum; a small cerebellar vermis; and a thin pons with a disproportionately large tectum (white arrow). Axial T2WI (B–D from superior to inferior) reveals severe ventriculomegaly. There is diffuse cortical dysgyria with bilateral frontal lobe band heterotopia (B). More inferiorly, there are abnormally enlarged caudates with fused striata (C) and an asymmetric, small pons (D), smaller on the right (black arrowhead) with a central cleft.

Patients with TUBA1A mutations. Midline sagittal T1WI in a 2-day-old patient (A) shows a thick, dysmorphic corpus callosum; a small cerebellar vermis; and a thin pons with a disproportionately large tectum. Axial T2WI in the same patient (B) shows cortical lissencephaly with a cell sparse zone, enlarged caudate heads with fused striata, and mild ventriculomegaly. Midline sagittal (C) and axial (D) T1WI from a different 3-year-old patient with TUBA1A mutation reveals contrasting dysgyric cortex (D) and a thin corpus callosum with an absent genu and rostrum (C). Again note a thin pons and moderate ventriculomegaly.

Patients with microtubule-associated protein mutations. Midline sagittal T1WI (A), axial T1WI (B), and T2WI (C) in an 8-month-old patient with a DYNC1H1 mutation. An abnormal corpus callosum with an absent inferior genu and rostrum and an L-shaped angulation of the body and splenium with small pons (A) are noted. Axial images (B and C) reveal parietal pachygyria with a cell sparse zone. Midline sagittal T1WI in a 7-year-old patient with a DCX mutation shows normal midline structures, including the corpus callosum, pons, cerebellar vermis, and tectum (D). Axial images from the same patient with a DCX mutation (E and F) reveal diffuse shallow sulci consistent with pachygyria and moderate band heterotopia. Midline sagittal T1WI from a 33-year-old patient with a LIS1 mutation (G) demonstrates a small anterior vermis and pons, with a mildly dysmorphic corpus callosum (small inferior genu and short splenium). Axial T2WI (H and I) from the same patient with a LIS1 mutation shows a typical cortical anteroposterior gradient with frontal pachygyria progressing to agyria in the parietal and occipital lobes. A thin cell sparse zone is present in the parietal and occipital lobes (H, white arrows). The basal ganglia are normal (I).