TUBB2B and tubulinopathy: Individual i086n had complete agenesis corpus callosum and additionally manifested unilateral optic nerve hypoplasia, a feature linked to TUBA8-associated tubulinopathy [6] but also described in individuals with TUBB2B [69] and TUBB3 [9] variants and present in 7/35 (20.0%) of individuals with TUBA1A-associated tubulinopathy.