TUBB3 E410K syndrome: Case report and review of the clinical spectrum of TUBB3 mutations.
The tubulinopathies refer to a wide range of brain malformations caused by mutations in one of the seven genes encoding different tubulin's isotypes. The β-tubulin isotype III (TUBB3) gene has a primary function in nervous system development and axon generation and maintenance, due to its neuron-specific expression pattern. A recurrent heterozygous mutation, c.1228G > A; p.E410K, in TUBB3 gene is responsible of a rare disorder clinically characterized by congenital fibrosis of the extraocular muscle type 3 (CFEOM3), intellectual disability and a wide range of neurological and endocrine abnormalities. Other mutations have been described spanning the entire gene and genotype-phenotype correlations have been proposed. We report on a 3-year-old boy in whom clinical exome sequencing allowed to identify a de novo TUBB3 E410K mutation as the molecular cause underlying a complex phenotype characterized by a severe bilateral palpebral ptosis refractory to eye surgery, psychomotor delay, absent speech, hypogonadism, celiac disease, and cyclic vomiting. Brain MRI revealed thinning of the corpus callosum with no evidence of malformation cortical dysplasia. We reviewed available records of patients with TUBB3 E410K mutation and compared their phenotype with the clinical outcome of patients with other mutations in TUBB3 gene. The present study confirms that TUBB3 E410K results in a clinically recognizable phenotype, unassociated to the distinct cortical dysplasia caused by other mutations in the same gene. Early molecular characterization of TUBB3 E410K syndrome is critical for targeted genetic counseling and prompt prospective care in term of neurological, ophthalmological, endocrine, and gastrointestinal follow-up.
['Dentici|Maria L|ML|https://orcid.org/0000-0002-9505-5906', 'Maglione|Vittorio|V|', 'Agolini|Emanuele|E|https://orcid.org/0000-0001-6543-6225', 'Catena|Gino|G|', 'Capolino|Rossella|R|', 'Lanari|Valentina|V|', 'Novelli|Antonio|A|', 'Sinibaldi|Lorenzo|L|', 'Vecchio|Davide|D|', 'Gonfiantini|Michaela V|MV|', 'Macchiaiolo|Marina|M|https://orcid.org/0000-0001-7409-8299', 'Digilio|Maria C|MC|', 'Dallapiccola|Bruno|B|', 'Bartuli|Andrea|A|']
D001921:Brain D002675:Child, Preschool D005355:Fibrosis D018507:Gene Expression Regulation, Developmental D056726:Genetic Association Studies D020022:Genetic Predisposition to Disease D006801:Humans D008607:Intellectual Disability D008297:Male D054220:Malformations of Cortical Development D009474:Neurons D009886:Ophthalmoplegia D014404:Tubulin D000073359:Whole Exome Sequencing
TUBB3 E410K syndrome tubulinopathy congenital fibrosis of extraocular muscle type 3 (CFEOM3) cortical development microtubule dysfunction