A Complex Cortical Malformation Caused by a Mutation in the Tubulin-Encoding TUBB3 Gene

Tubulinopathy commonly refers to complex congenital and non-progressive brain malformations caused by mutations in the tubulin genes. Among tubulin-encoding genes, TUBB3 has rarely been reported as a cause of complex cortical malformations. Herein, we report a case of tubulinopathy in a 21-month-old boy who presented with delayed development. He could not walk on his own and was not able to speak more than five words. Physical examination revealed right esotropia and hypotonia of the lower extremities. MRI showed dysmorphic brainstem and dysmorphic and hypertrophic basal ganglia. The right thalamus was relatively smaller than the left one. The cerebellum showed disorganization of the cerebellar folia. DNA sequencing revealed a missense mutation of the TUBB3 gene.