Two unique TUBB3 mutations cause both CFEOM3 and malformations of cortical development

Am J Med Genet A. 2016 Feb;170A(2):297-305. doi: 10.1002/ajmg.a.37362. Epub 2015 Dec 6.


One set of missense mutations in the neuron specific beta tubulin isotype 3 (TUBB3) has been reported to cause malformations of cortical development (MCD), while a second set has been reported to cause isolated or syndromic Congenital Fibrosis of the Extraocular Muscles type 3 (CFEOM3). Because TUBB3 mutations reported to cause CFEOM had not been associated with cortical malformations, while mutations reported to cause MCD had not been associated with CFEOM or other forms of paralytic strabismus, it was hypothesized that each set of mutations might alter microtubule function differently. Here, however, we report two novel de novo heterozygous TUBB3 amino acid substitutions, G71R and G98S, in four patients with both MCD and syndromic CFEOM3. These patients present with moderately severe CFEOM3, nystagmus, torticollis, and developmental delay, and have intellectual and social disabilities. Neuroimaging reveals defective cortical gyration, as well as hypoplasia or agenesis of the corpus callosum and anterior commissure, malformations of hippocampi, thalami, basal ganglia and cerebella, and brainstem and cranial nerve hypoplasia. These new TUBB3 substitutions meld the two previously distinct TUBB3-associated phenotypes, and implicate similar microtubule dysfunction underlying both.

Keywords: TUBB3; congenital fibrosis of extraocular muscles; cortical development; tubulin; tubulinopathy.

Publication types

  • Case Reports
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Amino Acid Sequence
  • Amino Acid Substitution
  • Child
  • Child, Preschool
  • Eye Diseases, Hereditary / genetics*
  • Eye Diseases, Hereditary / pathology*
  • Female
  • Fibrosis
  • Humans
  • Male
  • Malformations of Cortical Development / genetics*
  • Malformations of Cortical Development / pathology*
  • Molecular Sequence Data
  • Mutation / genetics*
  • Ophthalmoplegia
  • Pedigree
  • Phenotype
  • Sequence Homology, Amino Acid
  • Tubulin / genetics*
  • Young Adult


  • TUBB3 protein, human
  • Tubulin

Supplementary concepts

  • Congenital Fibrosis of the Extraocular Muscles