👪

Inheritance

1

Autosomal dominant inheritance HP:0000006

Autosomal dominant inheritance

Show evidence (1 reference)

PMID:23246003 SUPPORT Human Clinical

"We report the occurrence of three microcephalic patients with structural brain abnormalities harboring de novo mutations in TUBB5 (M299V, V353I, and E401K)."

The founding human case series reports de novo TUBB5 missense variants in three unrelated affected individuals, supporting dominant, typically sporadic inheritance.

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Discussions and Knowledge Gaps

2

Are the progenitor cell-cycle, spindle-orientation, apoptosis, and migration defects observed in mouse Tubb5 models conserved in human radial glia, outer-radial-glia-like cells, and cortical organoids carrying pathogenic TUBB/TUBB5 variants?

HUMAN MODEL MISMATCH OPEN gap_tubb_tubb5_human_organoid_translatability

Attached to

pathophysiology#Progenitor Cell-Cycle and Spindle Dysfunction pathophysiology#p53-Associated Apoptosis and Progenitor Pool Distortion pathophysiology#Impaired Neurogenic Division and Migration

The strongest mechanistic evidence is mouse based, while the Falcon report did not identify a direct TUBB/TUBB5 human iPSC or organoid disease model. Human cortical expansion depends on outer radial glia and OSVZ biology, so a human organoid/iPSC test is needed before assuming the mouse progenitor apoptosis branch fully explains the human microcephaly phenotype.

Proposed experiments

TUBB/TUBB5 isogenic cortical-organoid progenitor and apoptosis experiment

isogenic cortical organoid progenitor perturbation experiment

exp_tubb_tubb5_isogenic_organoid_progenitor_apoptosis

Generate patient-derived or CRISPR-engineered human cortical organoids carrying M299V, V353I, E401K, or newer pathogenic TUBB/TUBB5 variants; compare mutant, isogenic-corrected, and knock-in organoids for microtubule dynamics, tubulin heterodimer assembly, progenitor cell-cycle timing, spindle orientation, p53 activation, apoptosis, neuronal output, and migration.

Model systems

TUBB/TUBB5 human iPSC-derived cortical organoid

Three-dimensional human cortical organoid carrying a pathogenic TUBB/TUBB5 variant, with matched isogenic correction and knock-in controls.

ORGANOID namo:Organoid link

human NCBITaxon:9606

cerebral cortex UBERON:0000956

neural progenitor cell CL:0011020 radial glial cell CL:0000681

Perturbations

Isogenic TUBB/TUBB5 variant correction or knock-in

pathophysiology#Altered TUBB/TUBB5 Beta-Tubulin Function

Correct a patient variant or introduce a pathogenic variant to separate variant effects from donor background.

Readouts

Progenitor mitosis, p53 activation, and apoptosis

pathophysiology#p53-Associated Apoptosis and Progenitor Pool Distortion

Quantify cell-cycle length, spindle orientation, ectopic progenitor markers, p53 activation, apoptotic cells, and upper-layer neuron output.

mitotic cell cycle GO:0000278 ↕ DYSREGULATED apoptotic process GO:0006915 ↑ INCREASED

immunostaining single-cell transcriptomic profiling

Direction: POSITIVE

Controls

Isogenic corrected organoids

Patient-derived variant organoids corrected to the reference sequence.

Isogenic knock-in organoids

Control-background organoids carrying the introduced pathogenic variant.

Decision criterion

The mouse-derived mechanism is supported if human variant organoids show delayed progenitor cell cycle, spindle orientation defects, p53 activation, increased apoptosis, reduced upper-layer neuron output, and/or migration defects that are rescued by correction and reproduced by knock-in.

Would support

pathophysiology#Progenitor Cell-Cycle and Spindle Dysfunction pathophysiology#p53-Associated Apoptosis and Progenitor Pool Distortion pathophysiology#Impaired Neurogenic Division and Migration

Show evidence (2 references)

PMID:26903504 SUPPORT Model Organism

"cause TUBB5-associated microcephaly by exploiting two new mouse models"

Identifies the main mechanistic evidence source as mouse models, which motivates a human/model translatability gap.

PMID:28111201 SUPPORT In Vitro

"Recent work has uncovered critical cellular and molecular differences between cortical development in humans and mice, further underscoring the need to develop human model systems."

Supports organoid/iPSC testing when mouse cortical-development mechanisms are being translated to human disease.

What is the full natural-history and phenotype range for TUBB/TUBB5-related microcephaly beyond the three original cases and small tubulinopathy cohort counts?

KNOWLEDGE GAP OPEN gap_tubb_tubb5_natural_history_and_phenotype_breadth

Attached to

phenotypes#Global Developmental Delay / Intellectual Disability phenotypes#Polymicrogyria-like Cortical Dysplasia / Simplified Gyral Pattern

The entry is supported by a strong founding case series and model mechanism, but TUBB/TUBB5-specific longitudinal outcomes, seizure frequency, genotype- phenotype correlations, and variant-class effects remain much thinner than for TUBA1A or TUBB2B.

⚙

Pathophysiology

5

Altered TUBB/TUBB5 Beta-Tubulin Function

Pathogenic variants in the beta-tubulin isotype historically named TUBB5 alter chaperone-dependent tubulin heterodimer assembly and microtubule function. The upstream lesion is not simply a generic microcephaly label: different missense variants perturb the beta-tubulin folding/assembly machinery in different ways and feed both progenitor cell-cycle and neuronal migration branches.

neural progenitor cell CL:0011020 migrating cortical neuron CL:0000540

TUBB (formerly TUBB5) hgnc:20778

tubulin heterodimer assembly GO:0007021 ↕ DYSREGULATED microtubule cytoskeleton organization GO:0000226 ↕ DYSREGULATED

Downstream

Progenitor Cell-Cycle and Spindle Dysfunction Altered beta-tubulin function perturbs neural progenitor cell-cycle progression and spindle orientation.

Impaired Neurogenic Division and Migration Altered beta-tubulin function also changes the position of migrating neurons and disrupts migration-dependent cortical organization.

Show evidence (2 references)

PMID:23246003 SUPPORT In Vitro

"These mutant proteins, which affect the chaperone-dependent assembly of tubulin heterodimers in different ways"

Establishes variant-specific disruption of chaperone-dependent tubulin heterodimer assembly as the upstream beta-tubulin lesion.

PMID:23246003 SUPPORT Model Organism

"Tubb5 is expressed in neurogenic progenitors in the mouse and that its depletion in vivo perturbs the cell cycle of progenitors and alters the position of migrating neurons."

Separately classifies the in vivo mouse depletion data supporting progenitor cell-cycle and neuronal-position effects.

Progenitor Cell-Cycle and Spindle Dysfunction

Tubb/TUBB5 dysfunction affects neurogenic progenitors during corticogenesis. In the founding study, Tubb5 depletion perturbed progenitor cell-cycle progression and altered neuron position; in the knock-in mouse model, the E401K allele produced delayed cell-cycle progression, ectopic progenitor markers, and spindle-orientation defects. This progenitor branch is the main reason to model TUBB/TUBB5-related microcephaly separately from beta-tubulin disorders whose central skeleton is postmitotic neuronal migration.

neural progenitor cell CL:0011020 radial glial cell CL:0000681

mitotic cell cycle GO:0000278 ↕ DYSREGULATED mitotic spindle organization GO:0007052 ↕ DYSREGULATED cell division GO:0051301 ↕ DYSREGULATED

Downstream

p53-Associated Apoptosis and Progenitor Pool Distortion Cell-cycle and spindle defects trigger cell death and change the progenitor and neuronal output of the developing cortex.

Show evidence (3 references)

PMID:23246003 SUPPORT Model Organism

"Tubb5 is expressed in neurogenic progenitors in the mouse and that its depletion in vivo perturbs the cell cycle of progenitors and alters the position of migrating neurons."

Shows that Tubb5 acts in neurogenic progenitors and that depletion alters progenitor cell cycle and migrating neuron position.

PMID:26903504 SUPPORT Model Organism

"associated with a delay in cell cycle progression and ectopic DNA elements in progenitors"

Supports delayed progenitor cell-cycle progression as a Tubb5-dependent mechanism in mouse.

PMID:26903504 SUPPORT Model Organism

"we report ectopic Sox2-positive progenitors and defects in spindle orientation"

Supports progenitor mislocalization and spindle-orientation defects in the Tubb5 E401K knock-in model.

p53-Associated Apoptosis and Progenitor Pool Distortion

Tubb5 mouse models show that the microcephaly branch is driven by abnormal cell survival and progenitor-output effects, not only by altered neuronal migration. The E401K knock-in and loss-of-function models produce profound microcephaly with loss of upper-layer neurons, massive apoptosis, and p53 upregulation, making p53-associated cell death a central mechanistic branch.

neural progenitor cell CL:0011020 cortical neuron CL:0000540

apoptotic process GO:0006915 ↑ INCREASED maintenance of cell number GO:0098727 ↓ DECREASED neurogenesis GO:0022008 ↕ DYSREGULATED

Downstream

Microcephaly and Structural Brain Abnormalities Progenitor-pool distortion and apoptosis reduce cortical neuron output and produce the small-brain phenotype with associated structural malformations.

Show evidence (2 references)

PMID:26903504 SUPPORT Model Organism

"present with profound microcephaly due to a loss of upper-layer neurons that correlates with massive apoptosis and upregulation of p53."

Demonstrates the mouse microcephaly mechanism: upper-layer neuron loss with apoptosis and p53 upregulation.

PMID:26903504 SUPPORT Model Organism

"demonstrates that the cellular pathology driving TUBB5-associated microcephaly is cell death."

Directly identifies cell death as the cellular pathology driving the TUBB5-associated microcephaly model.

Impaired Neurogenic Division and Migration

TUBB/TUBB5 disease also has a migration and cortical-organization branch: Tubb5 depletion alters the position of migrating neurons, and tubulinopathy cohorts place TUBB5 among genes whose malformations include focal or multifocal polymicrogyria-like cortical dysplasia and simplified gyration. This branch is secondary to the progenitor-centered microcephaly skeleton but remains part of the pathograph.

migrating cortical neuron CL:0000540

neuron migration GO:0001764 ↓ DECREASED cerebral cortex development GO:0021987 ↕ DYSREGULATED

Downstream

Microcephaly and Structural Brain Abnormalities Migration and cortical organization defects contribute to the cortical dysgyria and structural brain abnormalities observed in affected individuals.

Show evidence (2 references)

PMID:23246003 SUPPORT Model Organism

"disrupt neurogenic division and/or migration in vivo."

Links TUBB5 mutant proteins to disrupted neurogenic division and migration in vivo.

PMID:24860126 SUPPORT Human Clinical

"TUBB3 and TUBB5 mutations cause milder malformations with focal or multifocal polymicrogyria-like cortical dysplasia with abnormal and simplified gyral pattern."

Places TUBB5 in the tubulinopathy subgroup with focal/multifocal polymicrogyria-like cortical dysplasia and simplified gyration.

Microcephaly and Structural Brain Abnormalities

The clinical-anatomical endpoint is microcephaly with structural brain abnormalities: dysmorphic basal ganglia, corpus callosum anomalies, simplified or polymicrogyria-like gyral pattern, and variable hindbrain involvement. This node is the shared endpoint of the progenitor apoptosis branch and the microtubule-dependent neuronal migration branch.

cerebral cortex development GO:0021987 ↕ DYSREGULATED

cerebral cortex UBERON:0000956 basal ganglion UBERON:0002420

Downstream

Microcephaly The structural brain endpoint includes the defining microcephaly phenotype in TUBB/TUBB5 disease.

Polymicrogyria-like Cortical Dysplasia / Simplified Gyral Pattern The endpoint structural brain abnormality includes the simplified/polymicrogyria-like cortical malformation pattern.

Abnormal Basal Ganglia Morphology Dysmorphic basal ganglia are represented as an extracortical structural abnormality downstream of tubulinopathy brain malformation.

Show evidence (2 references)

PMID:23246003 SUPPORT Human Clinical

"We report the occurrence of three microcephalic patients with structural brain abnormalities harboring de novo mutations in TUBB5 (M299V, V353I, and E401K)."

Directly establishes the human endpoint: microcephaly with structural brain abnormalities due to de novo TUBB5 variants.

PMID:24860126 SUPPORT Human Clinical

"three in TUBB5 (2.8%)"

Shows that TUBB5 is a rare but recognized tubulinopathy gene in a large complex cortical malformation cohort.

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Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.

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Phenotypes

5

Head and Neck 1

Microcephaly Microcephaly HP:0000252

Show evidence (1 reference)

PMID:23246003 SUPPORT Human Clinical

"We report the occurrence of three microcephalic patients with structural brain abnormalities harboring de novo mutations in TUBB5 (M299V, V353I, and E401K)."

Establishes microcephaly as the defining phenotype in the human TUBB5 case series.

Nervous System 4

Polymicrogyria-like Cortical Dysplasia / Simplified Gyral Pattern Polymicrogyria HP:0002126

Show evidence (1 reference)

PMID:24860126 SUPPORT Human Clinical

"TUBB3 and TUBB5 mutations cause milder malformations with focal or multifocal polymicrogyria-like cortical dysplasia with abnormal and simplified gyral pattern."

Supports the cortical dysplasia/simplified gyral phenotype for TUBB5.

Abnormal Basal Ganglia Morphology Abnormal basal ganglia morphology HP:0002134

Show evidence (1 reference)

PMID:24860126 SUPPORT Human Clinical

"Dysmorphic basal ganglia are the hallmark of tubulinopathies (found in 75% of cases)"

Establishes dysmorphic basal ganglia as a tubulinopathy imaging hallmark.

Corpus Callosum Abnormality Abnormal corpus callosum morphology HP:0001273

Show evidence (1 reference)

PMID:24860126 SUPPORT Human Clinical

"Tubulinopathies are also characterized by a high prevalence of corpus callosum agenesis (32/80; 40%)"

Documents corpus callosum agenesis as a common tubulinopathy structural feature.

Global Developmental Delay / Intellectual Disability Global developmental delay HP:0001263

🧬

Genetic Associations

1

TUBB (Causative)

Gene: TUBB (formerly TUBB5) hgnc:20778

Show evidence (1 reference)

PMID:23246003 SUPPORT Human Clinical

"We report the occurrence of three microcephalic patients with structural brain abnormalities harboring de novo mutations in TUBB5 (M299V, V353I, and E401K)."

The historical TUBB5 symbol in the primary article maps to current HGNC symbol TUBB; the case series directly establishes causative variants in this gene.

💊

Medical Actions

3

Supportive and Rehabilitative Care

Action: supportive care MAXO:0000950

Management is supportive, including developmental, physical, occupational, speech/language, feeding, vision/oculomotor, and epilepsy surveillance services tailored to the individual's structural brain malformation and neurodevelopmental needs.

Anti-Seizure Medication

Action: pharmacotherapy Ontology label: Pharmacotherapy NCIT:C15986

Standard anti-seizure medication is used when seizures occur. No disease-modifying therapy for the beta-tubulin progenitor/migration mechanism is established.

Genetic Counseling

Action: Genetic Counseling NCIT:C15240

Genetic counseling should use current TUBB nomenclature, explain the historical TUBB5 literature, and discuss de novo dominant inheritance with residual recurrence risk from possible parental mosaicism.

{ }

Source YAML

click to show

name: TUBB/TUBB5-related Microcephaly
creation_date: "2026-06-12T03:31:46Z"
category: Mendelian
description: >-
  TUBB/TUBB5-related microcephaly is a beta-tubulin neurodevelopmental disorder
  caused by heterozygous de novo missense variants in the gene historically
  reported as TUBB5 and currently represented by HGNC as TUBB. It is modeled as a
  distinct disease entry because its skeleton is centered on embryonic
  neurogenesis and cortical size: altered beta-tubulin folding, heterodimer
  assembly, and microtubule function perturb neural progenitor cell-cycle
  progression, spindle orientation, neurogenic division, and neuronal migration;
  in mouse models, the microcephaly mechanism includes p53-associated apoptosis
  and loss of upper-layer neurons. The human phenotype combines congenital or
  early microcephaly with structural brain abnormalities such as dysmorphic
  basal ganglia, corpus callosum abnormality, simplified or polymicrogyria-like
  cortical malformation, and variable brainstem/cerebellar involvement, together
  with developmental delay, intellectual disability, motor and speech delay, and
  occasional seizures. This is therefore split from TUBB2A/TUBB2B cortical
  malformation and TUBB3 disease, while sharing module-level microtubule
  apparatus biology with the broader tubulinopathy family.
parents:
- congenital nervous system disorder
- disorder of development or morphogenesis
- hereditary neurological disease
- primary microcephaly
references:
- reference: PMID:23246003
  title: Mutations in the beta-tubulin gene TUBB5 cause microcephaly with structural brain abnormalities.
- reference: PMID:26903504
  title: Mutations in the murine homologue of TUBB5 cause microcephaly by perturbing cell cycle progression and inducing p53-associated apoptosis.
- reference: PMID:24860126
  title: "The wide spectrum of tubulinopathies: what are the key features for the diagnosis?"
- reference: PMID:28111201
  title: Human iPSC-Derived Cerebral Organoids Model Cellular Features of Lissencephaly and Reveal Prolonged Mitosis of Outer Radial Glia.
inheritance:
- name: Autosomal dominant inheritance
  inheritance_term:
    preferred_term: Autosomal dominant inheritance
    term:
      id: HP:0000006
      label: Autosomal dominant inheritance
  evidence:
  - reference: PMID:23246003
    reference_title: Mutations in the beta-tubulin gene TUBB5 cause microcephaly with structural brain abnormalities.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We report the occurrence of three microcephalic patients with structural
      brain abnormalities harboring de novo mutations in TUBB5 (M299V, V353I,
      and E401K).
    explanation: >-
      The founding human case series reports de novo TUBB5 missense variants in
      three unrelated affected individuals, supporting dominant, typically
      sporadic inheritance.
pathophysiology:
- name: Altered TUBB/TUBB5 Beta-Tubulin Function
  conforms_to: microtubule_dependent_neuronal_migration_failure#Microtubule Apparatus Perturbation
  description: >-
    Pathogenic variants in the beta-tubulin isotype historically named TUBB5
    alter chaperone-dependent tubulin heterodimer assembly and microtubule
    function. The upstream lesion is not simply a generic microcephaly label:
    different missense variants perturb the beta-tubulin folding/assembly
    machinery in different ways and feed both progenitor cell-cycle and neuronal
    migration branches.
  genes:
  - preferred_term: TUBB (formerly TUBB5)
    term:
      id: hgnc:20778
      label: TUBB
  cell_types:
  - preferred_term: neural progenitor cell
    term:
      id: CL:0011020
      label: neural progenitor cell
  - preferred_term: migrating cortical neuron
    term:
      id: CL:0000540
      label: neuron
  biological_processes:
  - preferred_term: tubulin heterodimer assembly
    term:
      id: GO:0007021
      label: tubulin complex assembly
    modifier: DYSREGULATED
  - preferred_term: microtubule cytoskeleton organization
    term:
      id: GO:0000226
      label: microtubule cytoskeleton organization
    modifier: DYSREGULATED
  evidence:
  - reference: PMID:23246003
    reference_title: Mutations in the beta-tubulin gene TUBB5 cause microcephaly with structural brain abnormalities.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      These mutant proteins, which affect the chaperone-dependent assembly of
      tubulin heterodimers in different ways
    explanation: >-
      Establishes variant-specific disruption of chaperone-dependent tubulin
      heterodimer assembly as the upstream beta-tubulin lesion.
  - reference: PMID:23246003
    reference_title: Mutations in the beta-tubulin gene TUBB5 cause microcephaly with structural brain abnormalities.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Tubb5 is expressed in neurogenic progenitors in the mouse and that its
      depletion in vivo perturbs the cell cycle of progenitors and alters the
      position of migrating neurons.
    explanation: >-
      Separately classifies the in vivo mouse depletion data supporting
      progenitor cell-cycle and neuronal-position effects.
  downstream:
  - target: Progenitor Cell-Cycle and Spindle Dysfunction
    description: >-
      Altered beta-tubulin function perturbs neural progenitor cell-cycle
      progression and spindle orientation.
  - target: Impaired Neurogenic Division and Migration
    description: >-
      Altered beta-tubulin function also changes the position of migrating
      neurons and disrupts migration-dependent cortical organization.
- name: Progenitor Cell-Cycle and Spindle Dysfunction
  conforms_to: neural_progenitor_centrosome_spindle_dysfunction#Abnormal Progenitor Division and Fate Choice
  description: >-
    Tubb/TUBB5 dysfunction affects neurogenic progenitors during corticogenesis.
    In the founding study, Tubb5 depletion perturbed progenitor cell-cycle
    progression and altered neuron position; in the knock-in mouse model, the
    E401K allele produced delayed cell-cycle progression, ectopic progenitor
    markers, and spindle-orientation defects. This progenitor branch is the main
    reason to model TUBB/TUBB5-related microcephaly separately from beta-tubulin
    disorders whose central skeleton is postmitotic neuronal migration.
  cell_types:
  - preferred_term: neural progenitor cell
    term:
      id: CL:0011020
      label: neural progenitor cell
  - preferred_term: radial glial cell
    term:
      id: CL:0000681
      label: radial glial cell
  biological_processes:
  - preferred_term: mitotic cell cycle
    term:
      id: GO:0000278
      label: mitotic cell cycle
    modifier: DYSREGULATED
  - preferred_term: mitotic spindle organization
    term:
      id: GO:0007052
      label: mitotic spindle organization
    modifier: DYSREGULATED
  - preferred_term: cell division
    term:
      id: GO:0051301
      label: cell division
    modifier: DYSREGULATED
  evidence:
  - reference: PMID:23246003
    reference_title: Mutations in the beta-tubulin gene TUBB5 cause microcephaly with structural brain abnormalities.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Tubb5 is expressed in neurogenic progenitors in the mouse and that its
      depletion in vivo perturbs the cell cycle of progenitors and alters the
      position of migrating neurons.
    explanation: >-
      Shows that Tubb5 acts in neurogenic progenitors and that depletion alters
      progenitor cell cycle and migrating neuron position.
  - reference: PMID:26903504
    reference_title: Mutations in the murine homologue of TUBB5 cause microcephaly by perturbing cell cycle progression and inducing p53-associated apoptosis.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      associated with a delay in cell cycle progression and ectopic DNA elements
      in progenitors
    explanation: >-
      Supports delayed progenitor cell-cycle progression as a Tubb5-dependent
      mechanism in mouse.
  - reference: PMID:26903504
    reference_title: Mutations in the murine homologue of TUBB5 cause microcephaly by perturbing cell cycle progression and inducing p53-associated apoptosis.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      we report ectopic Sox2-positive progenitors and defects in spindle
      orientation
    explanation: >-
      Supports progenitor mislocalization and spindle-orientation defects in
      the Tubb5 E401K knock-in model.
  downstream:
  - target: p53-Associated Apoptosis and Progenitor Pool Distortion
    description: >-
      Cell-cycle and spindle defects trigger cell death and change the
      progenitor and neuronal output of the developing cortex.
- name: p53-Associated Apoptosis and Progenitor Pool Distortion
  conforms_to: neural_progenitor_centrosome_spindle_dysfunction#Progenitor Pool Distortion
  description: >-
    Tubb5 mouse models show that the microcephaly branch is driven by abnormal
    cell survival and progenitor-output effects, not only by altered neuronal
    migration. The E401K knock-in and loss-of-function models produce profound
    microcephaly with loss of upper-layer neurons, massive apoptosis, and p53
    upregulation, making p53-associated cell death a central mechanistic branch.
  cell_types:
  - preferred_term: neural progenitor cell
    term:
      id: CL:0011020
      label: neural progenitor cell
  - preferred_term: cortical neuron
    term:
      id: CL:0000540
      label: neuron
  biological_processes:
  - preferred_term: apoptotic process
    term:
      id: GO:0006915
      label: apoptotic process
    modifier: INCREASED
  - preferred_term: maintenance of cell number
    term:
      id: GO:0098727
      label: maintenance of cell number
    modifier: DECREASED
  - preferred_term: neurogenesis
    term:
      id: GO:0022008
      label: neurogenesis
    modifier: DYSREGULATED
  evidence:
  - reference: PMID:26903504
    reference_title: Mutations in the murine homologue of TUBB5 cause microcephaly by perturbing cell cycle progression and inducing p53-associated apoptosis.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      present with profound microcephaly due to a loss of upper-layer neurons
      that correlates with massive apoptosis and upregulation of p53.
    explanation: >-
      Demonstrates the mouse microcephaly mechanism: upper-layer neuron loss
      with apoptosis and p53 upregulation.
  - reference: PMID:26903504
    reference_title: Mutations in the murine homologue of TUBB5 cause microcephaly by perturbing cell cycle progression and inducing p53-associated apoptosis.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      demonstrates that the cellular pathology driving TUBB5-associated
      microcephaly is cell death.
    explanation: >-
      Directly identifies cell death as the cellular pathology driving the
      TUBB5-associated microcephaly model.
  downstream:
  - target: Microcephaly and Structural Brain Abnormalities
    description: >-
      Progenitor-pool distortion and apoptosis reduce cortical neuron output and
      produce the small-brain phenotype with associated structural
      malformations.
- name: Impaired Neurogenic Division and Migration
  conforms_to: microtubule_dependent_neuronal_migration_failure#Microtubule-Based Neuronal Motility Failure
  description: >-
    TUBB/TUBB5 disease also has a migration and cortical-organization branch:
    Tubb5 depletion alters the position of migrating neurons, and tubulinopathy
    cohorts place TUBB5 among genes whose malformations include focal or
    multifocal polymicrogyria-like cortical dysplasia and simplified gyration.
    This branch is secondary to the progenitor-centered microcephaly skeleton
    but remains part of the pathograph.
  cell_types:
  - preferred_term: migrating cortical neuron
    term:
      id: CL:0000540
      label: neuron
  biological_processes:
  - preferred_term: neuron migration
    term:
      id: GO:0001764
      label: neuron migration
    modifier: DECREASED
  - preferred_term: cerebral cortex development
    term:
      id: GO:0021987
      label: cerebral cortex development
    modifier: DYSREGULATED
  evidence:
  - reference: PMID:23246003
    reference_title: Mutations in the beta-tubulin gene TUBB5 cause microcephaly with structural brain abnormalities.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      disrupt neurogenic division and/or migration in vivo.
    explanation: >-
      Links TUBB5 mutant proteins to disrupted neurogenic division and
      migration in vivo.
  - reference: PMID:24860126
    reference_title: "The wide spectrum of tubulinopathies: what are the key features for the diagnosis?"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      TUBB3 and TUBB5 mutations cause milder malformations with focal or
      multifocal polymicrogyria-like cortical dysplasia with abnormal and
      simplified gyral pattern.
    explanation: >-
      Places TUBB5 in the tubulinopathy subgroup with focal/multifocal
      polymicrogyria-like cortical dysplasia and simplified gyration.
  downstream:
  - target: Microcephaly and Structural Brain Abnormalities
    description: >-
      Migration and cortical organization defects contribute to the cortical
      dysgyria and structural brain abnormalities observed in affected
      individuals.
- name: Microcephaly and Structural Brain Abnormalities
  conforms_to: neural_progenitor_centrosome_spindle_dysfunction#Abnormal Cortical Neuron Output and Gyration
  description: >-
    The clinical-anatomical endpoint is microcephaly with structural brain
    abnormalities: dysmorphic basal ganglia, corpus callosum anomalies,
    simplified or polymicrogyria-like gyral pattern, and variable hindbrain
    involvement. This node is the shared endpoint of the progenitor apoptosis
    branch and the microtubule-dependent neuronal migration branch.
  locations:
  - preferred_term: cerebral cortex
    term:
      id: UBERON:0000956
      label: cerebral cortex
  - preferred_term: basal ganglion
    term:
      id: UBERON:0002420
      label: basal ganglion
  biological_processes:
  - preferred_term: cerebral cortex development
    term:
      id: GO:0021987
      label: cerebral cortex development
    modifier: DYSREGULATED
  evidence:
  - reference: PMID:23246003
    reference_title: Mutations in the beta-tubulin gene TUBB5 cause microcephaly with structural brain abnormalities.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We report the occurrence of three microcephalic patients with structural
      brain abnormalities harboring de novo mutations in TUBB5 (M299V, V353I,
      and E401K).
    explanation: >-
      Directly establishes the human endpoint: microcephaly with structural
      brain abnormalities due to de novo TUBB5 variants.
  - reference: PMID:24860126
    reference_title: "The wide spectrum of tubulinopathies: what are the key features for the diagnosis?"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      three in TUBB5 (2.8%)
    explanation: >-
      Shows that TUBB5 is a rare but recognized tubulinopathy gene in a large
      complex cortical malformation cohort.
  downstream:
  - target: Microcephaly
    causal_link_type: DIRECT
    description: The structural brain endpoint includes the defining microcephaly phenotype in TUBB/TUBB5 disease.
    evidence:
    - reference: PMID:23246003
      reference_title: Mutations in the beta-tubulin gene TUBB5 cause microcephaly with structural brain abnormalities.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        We report the occurrence of three microcephalic patients with structural
        brain abnormalities harboring de novo mutations in TUBB5 (M299V, V353I,
        and E401K).
      explanation: This directly establishes microcephaly with structural brain abnormalities in human TUBB5 patients.
  - target: Polymicrogyria-like Cortical Dysplasia / Simplified Gyral Pattern
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - Abnormal cortical gyration downstream of beta-tubulin neurogenesis and migration defects
    description: The endpoint structural brain abnormality includes the simplified/polymicrogyria-like cortical malformation pattern.
    evidence:
    - reference: PMID:24860126
      reference_title: "The wide spectrum of tubulinopathies: what are the key features for the diagnosis?"
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        TUBB3 and TUBB5 mutations cause milder malformations with focal or
        multifocal polymicrogyria-like cortical dysplasia with abnormal and
        simplified gyral pattern.
      explanation: This supports the TUBB5 polymicrogyria-like/simplified gyral phenotype.
  - target: Abnormal Basal Ganglia Morphology
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - Tubulinopathy-associated deep grey matter dysmorphogenesis
    description: Dysmorphic basal ganglia are represented as an extracortical structural abnormality downstream of tubulinopathy brain malformation.
    evidence:
    - reference: PMID:24860126
      reference_title: "The wide spectrum of tubulinopathies: what are the key features for the diagnosis?"
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Dysmorphic basal ganglia are the hallmark of tubulinopathies (found in
        75% of cases)
      explanation: This supports basal-ganglia dysmorphism as a tubulinopathy structural-brain endpoint.
phenotypes:
- name: Microcephaly
  description: >-
    Microcephaly is the defining head-size phenotype in the founding human
    TUBB5 series and is recapitulated as profound microcephaly in Tubb5 mouse
    models.
  phenotype_term:
    preferred_term: Microcephaly
    term:
      id: HP:0000252
      label: Microcephaly
  evidence:
  - reference: PMID:23246003
    reference_title: Mutations in the beta-tubulin gene TUBB5 cause microcephaly with structural brain abnormalities.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We report the occurrence of three microcephalic patients with structural
      brain abnormalities harboring de novo mutations in TUBB5 (M299V, V353I,
      and E401K).
    explanation: >-
      Establishes microcephaly as the defining phenotype in the human TUBB5
      case series.
- name: Polymicrogyria-like Cortical Dysplasia / Simplified Gyral Pattern
  description: >-
    TUBB5 is associated with milder focal or multifocal polymicrogyria-like
    cortical dysplasia and simplified gyration within the tubulinopathy cortical
    malformation spectrum.
  phenotype_term:
    preferred_term: Polymicrogyria
    term:
      id: HP:0002126
      label: Polymicrogyria
  evidence:
  - reference: PMID:24860126
    reference_title: "The wide spectrum of tubulinopathies: what are the key features for the diagnosis?"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      TUBB3 and TUBB5 mutations cause milder malformations with focal or
      multifocal polymicrogyria-like cortical dysplasia with abnormal and
      simplified gyral pattern.
    explanation: >-
      Supports the cortical dysplasia/simplified gyral phenotype for TUBB5.
- name: Abnormal Basal Ganglia Morphology
  description: >-
    Dysmorphic basal ganglia are a hallmark of tubulinopathies and are part of
    the structural brain abnormality pattern that should be assessed in
    TUBB/TUBB5-related microcephaly.
  phenotype_term:
    preferred_term: Abnormal basal ganglia morphology
    term:
      id: HP:0002134
      label: Abnormal basal ganglia morphology
  evidence:
  - reference: PMID:24860126
    reference_title: "The wide spectrum of tubulinopathies: what are the key features for the diagnosis?"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Dysmorphic basal ganglia are the hallmark of tubulinopathies (found in 75%
      of cases)
    explanation: >-
      Establishes dysmorphic basal ganglia as a tubulinopathy imaging hallmark.
- name: Corpus Callosum Abnormality
  description: >-
    Corpus callosum agenesis or dysmorphism is a frequent tubulinopathy
    structural brain abnormality and was part of the TUBB5 case-image summary in
    Falcon research.
  phenotype_term:
    preferred_term: Abnormal corpus callosum morphology
    term:
      id: HP:0001273
      label: Abnormal corpus callosum morphology
  evidence:
  - reference: PMID:24860126
    reference_title: "The wide spectrum of tubulinopathies: what are the key features for the diagnosis?"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Tubulinopathies are also characterized by a high prevalence of corpus
      callosum agenesis (32/80; 40%)
    explanation: >-
      Documents corpus callosum agenesis as a common tubulinopathy structural
      feature.
- name: Global Developmental Delay / Intellectual Disability
  description: >-
    Developmental and cognitive impairment are expected clinical outcomes of
    TUBB/TUBB5-related microcephaly with structural brain abnormalities.
  phenotype_term:
    preferred_term: Global developmental delay
    term:
      id: HP:0001263
      label: Global developmental delay
genetic:
- name: TUBB
  association: Causative
  gene_term:
    preferred_term: TUBB (formerly TUBB5)
    term:
      id: hgnc:20778
      label: TUBB
  evidence:
  - reference: PMID:23246003
    reference_title: Mutations in the beta-tubulin gene TUBB5 cause microcephaly with structural brain abnormalities.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We report the occurrence of three microcephalic patients with structural
      brain abnormalities harboring de novo mutations in TUBB5 (M299V, V353I,
      and E401K).
    explanation: >-
      The historical TUBB5 symbol in the primary article maps to current HGNC
      symbol TUBB; the case series directly establishes causative variants in
      this gene.
treatments:
- name: Supportive and Rehabilitative Care
  description: >-
    Management is supportive, including developmental, physical, occupational,
    speech/language, feeding, vision/oculomotor, and epilepsy surveillance
    services tailored to the individual's structural brain malformation and
    neurodevelopmental needs.
  treatment_term:
    preferred_term: supportive care
    term:
      id: MAXO:0000950
      label: supportive care
- name: Anti-Seizure Medication
  description: >-
    Standard anti-seizure medication is used when seizures occur. No
    disease-modifying therapy for the beta-tubulin progenitor/migration
    mechanism is established.
  treatment_term:
    preferred_term: pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
- name: Genetic Counseling
  description: >-
    Genetic counseling should use current TUBB nomenclature, explain the
    historical TUBB5 literature, and discuss de novo dominant inheritance with
    residual recurrence risk from possible parental mosaicism.
  treatment_term:
    preferred_term: Genetic Counseling
    term:
      id: NCIT:C15240
      label: Genetic Counseling
discussions:
- discussion_id: gap_tubb_tubb5_human_organoid_translatability
  prompt: >-
    Are the progenitor cell-cycle, spindle-orientation, apoptosis, and migration
    defects observed in mouse Tubb5 models conserved in human radial glia,
    outer-radial-glia-like cells, and cortical organoids carrying pathogenic
    TUBB/TUBB5 variants?
  kind: HUMAN_MODEL_MISMATCH
  status: OPEN
  attaches_to:
  - pathophysiology#Progenitor Cell-Cycle and Spindle Dysfunction
  - pathophysiology#p53-Associated Apoptosis and Progenitor Pool Distortion
  - pathophysiology#Impaired Neurogenic Division and Migration
  rationale: >-
    The strongest mechanistic evidence is mouse based, while the Falcon report
    did not identify a direct TUBB/TUBB5 human iPSC or organoid disease model.
    Human cortical expansion depends on outer radial glia and OSVZ biology, so
    a human organoid/iPSC test is needed before assuming the mouse progenitor
    apoptosis branch fully explains the human microcephaly phenotype.
  evidence:
  - reference: PMID:26903504
    reference_title: Mutations in the murine homologue of TUBB5 cause microcephaly by perturbing cell cycle progression and inducing p53-associated apoptosis.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      cause TUBB5-associated microcephaly by exploiting two new mouse models
    explanation: >-
      Identifies the main mechanistic evidence source as mouse models, which
      motivates a human/model translatability gap.
  - reference: PMID:28111201
    reference_title: Human iPSC-Derived Cerebral Organoids Model Cellular Features of Lissencephaly and Reveal Prolonged Mitosis of Outer Radial Glia.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      Recent work has uncovered critical cellular and molecular differences
      between cortical development in humans and mice, further underscoring the
      need to develop human model systems.
    explanation: >-
      Supports organoid/iPSC testing when mouse cortical-development mechanisms
      are being translated to human disease.
  proposed_experiments:
  - experiment_id: exp_tubb_tubb5_isogenic_organoid_progenitor_apoptosis
    name: TUBB/TUBB5 isogenic cortical-organoid progenitor and apoptosis experiment
    description: >-
      Generate patient-derived or CRISPR-engineered human cortical organoids
      carrying M299V, V353I, E401K, or newer pathogenic TUBB/TUBB5 variants;
      compare mutant, isogenic-corrected, and knock-in organoids for
      microtubule dynamics, tubulin heterodimer assembly, progenitor cell-cycle
      timing, spindle orientation, p53 activation, apoptosis, neuronal output,
      and migration.
    experiment_type:
      preferred_term: isogenic cortical organoid progenitor perturbation experiment
    model_systems:
    - name: TUBB/TUBB5 human iPSC-derived cortical organoid
      description: >-
        Three-dimensional human cortical organoid carrying a pathogenic
        TUBB/TUBB5 variant, with matched isogenic correction and knock-in
        controls.
      experimental_model_type: ORGANOID
      namo_type: namo:Organoid
      organism:
        preferred_term: human
        term:
          id: NCBITaxon:9606
          label: Homo sapiens
      tissue_term:
        preferred_term: cerebral cortex
        term:
          id: UBERON:0000956
          label: cerebral cortex
      cell_types:
      - preferred_term: neural progenitor cell
        term:
          id: CL:0011020
          label: neural progenitor cell
      - preferred_term: radial glial cell
        term:
          id: CL:0000681
          label: radial glial cell
      conditions:
      - TUBB/TUBB5-related microcephaly
      - progenitor cell-cycle dysfunction
      - p53-associated apoptosis
      cell_source: Patient-derived or CRISPR-engineered human induced pluripotent stem cells
      culture_system: Three-dimensional cortical organoid with live imaging, immunostaining, and single-cell profiling
    perturbations:
    - name: Isogenic TUBB/TUBB5 variant correction or knock-in
      target: pathophysiology#Altered TUBB/TUBB5 Beta-Tubulin Function
      description: >-
        Correct a patient variant or introduce a pathogenic variant to separate
        variant effects from donor background.
    readouts:
    - name: Progenitor mitosis, p53 activation, and apoptosis
      target: pathophysiology#p53-Associated Apoptosis and Progenitor Pool Distortion
      description: >-
        Quantify cell-cycle length, spindle orientation, ectopic progenitor
        markers, p53 activation, apoptotic cells, and upper-layer neuron output.
      biological_processes:
      - preferred_term: mitotic cell cycle
        term:
          id: GO:0000278
          label: mitotic cell cycle
        modifier: DYSREGULATED
      - preferred_term: apoptotic process
        term:
          id: GO:0006915
          label: apoptotic process
        modifier: INCREASED
      assays:
      - preferred_term: immunostaining
      - preferred_term: single-cell transcriptomic profiling
      direction: POSITIVE
    controls:
    - name: Isogenic corrected organoids
      description: Patient-derived variant organoids corrected to the reference sequence.
    - name: Isogenic knock-in organoids
      description: Control-background organoids carrying the introduced pathogenic variant.
    decision_criterion: >-
      The mouse-derived mechanism is supported if human variant organoids show
      delayed progenitor cell cycle, spindle orientation defects, p53 activation,
      increased apoptosis, reduced upper-layer neuron output, and/or migration
      defects that are rescued by correction and reproduced by knock-in.
    would_support:
    - pathophysiology#Progenitor Cell-Cycle and Spindle Dysfunction
    - pathophysiology#p53-Associated Apoptosis and Progenitor Pool Distortion
    - pathophysiology#Impaired Neurogenic Division and Migration
- discussion_id: gap_tubb_tubb5_natural_history_and_phenotype_breadth
  prompt: >-
    What is the full natural-history and phenotype range for TUBB/TUBB5-related
    microcephaly beyond the three original cases and small tubulinopathy cohort
    counts?
  kind: KNOWLEDGE_GAP
  status: OPEN
  attaches_to:
  - phenotypes#Global Developmental Delay / Intellectual Disability
  - phenotypes#Polymicrogyria-like Cortical Dysplasia / Simplified Gyral Pattern
  rationale: >-
    The entry is supported by a strong founding case series and model mechanism,
    but TUBB/TUBB5-specific longitudinal outcomes, seizure frequency, genotype-
    phenotype correlations, and variant-class effects remain much thinner than
    for TUBA1A or TUBB2B.
notes: >-
  Entry created from cortical-malformation epic 4098 (issue 4086), seeded from
  Romero, Bahi-Buisson & Francis 2018 and refined with Falcon deep research.
  The primary literature uses TUBB5; HGNC now resolves TUBB5 to current symbol
  TUBB (HGNC:20778), so this entry preserves both names in the title while using
  TUBB as the gene term. The disease is not lumped with generic primary
  microcephaly or generic tubulinopathy because its coherent skeleton combines
  beta-tubulin heterodimer/microtubule dysfunction with a progenitor cell-cycle,
  spindle, p53-apoptosis, and upper-layer neuron-output branch. It conforms
  mainly to the neural progenitor centrosome-spindle dysfunction module, with a
  secondary conformance to the microtubule-dependent neuronal migration module
  for the migration/cortical dysgyria branch. The Falcon report found no direct
  TUBB/TUBB5 organoid or iPSC disease model; the organoid experiment is included
  as a human/model mismatch knowledge gap, not as existing disease evidence.

📚

References & Deep Research

References

4

PMID:23246003

Mutations in the beta-tubulin gene TUBB5 cause microcephaly with structural brain abnormalities.

No top-level findings curated for this source.

PMID:26903504

Mutations in the murine homologue of TUBB5 cause microcephaly by perturbing cell cycle progression and inducing p53-associated apoptosis.

No top-level findings curated for this source.

PMID:24860126

The wide spectrum of tubulinopathies: what are the key features for the diagnosis?

No top-level findings curated for this source.

PMID:28111201

Human iPSC-Derived Cerebral Organoids Model Cellular Features of Lissencephaly and Reveal Prolonged Mitosis of Outer Radial Glia.

No top-level findings curated for this source.

Deep Research

1

Falcon ▸

Disease Characteristics Research Template

Edison Scientific Literature 25 citations 2026-06-11T20:46:31.124760

Question: You are an expert researcher providing comprehensive, well-cited information.

Provide detailed information focusing on: 1. Key concepts and definitions with current understanding 2. Recent developments and latest research (prioritize 2023-2024 sources) 3. Current applications and real-world implementations 4. Expert opinions and analysis from authoritative sources 5. Relevant statistics and data from recent studies

Format as a comprehensive research report with proper citations. Include URLs and publication dates where available. Always prioritize recent, authoritative sources and provide specific citations for all major claims.

Disease Characteristics Research Template

Target Disease

Disease Name: TUBB/TUBB5-related Microcephaly
MONDO ID: (if available)
Category: Mendelian

Research Objectives

Please provide a comprehensive research report on TUBB/TUBB5-related Microcephaly covering all of the disease characteristics listed below. This report will be used to populate a disease knowledge base entry. Be thorough and cite primary literature (PMID preferred) for all claims.

For each section, suggested databases/resources are listed. These are the first places you should search for information on each topic.

1. Disease Information

Search first: OMIM, Orphanet, ICD-10/ICD-11, MeSH, PubMed

What is the disease? Provide a concise overview.
What are the key identifiers? (OMIM, Orphanet, ICD-10/ICD-11, MeSH, Mondo)
What are the common synonyms and alternative names?
Is the information derived from individual patients (e.g., EHR) or aggregated disease-level resources?

2. Etiology

Disease Causal Factors: What are the primary causes? (genetic, environmental, infectious, mechanistic)
Risk Factors:

Search first: PubMed, Cochrane Library, UpToDate, clinical guidelines, ClinVar, ClinGen, GWAS Catalog, PheGenI, CTD, CDC, WHO, epidemiological databases
Genetic risk factors (causal variants, susceptibility loci, modifier genes)
Environmental risk factors (toxins, lifestyle, occupational exposures, age, sex, family history)
Protective Factors:

Search first: PubMed, Cochrane Library, clinical trial databases, GWAS Catalog, gnomAD, WHO, CDC, nutrition databases
Genetic protective factors (protective variants, modifier alleles)
Environmental protective factors (diet, lifestyle, exposures that reduce risk)
Gene-Environment Interactions: How do genetic and environmental factors interact to influence disease?

Search first: CTD, PubMed, PheGenI, GxE databases

3. Phenotypes

Search first: HPO (Human Phenotype Ontology), OMIM, Orphanet, PubMed, clinicaltrials.gov, MedDRA, SNOMED CT, DECIPHER, LOINC

For each phenotype, provide: - Phenotype type: symptoms, clinical signs, physical manifestations, behavioral changes, or laboratory abnormalities

For symptoms/signs: HPO, OMIM, Orphanet, PubMed For behavioral changes: HPO, DSM, RDoC (Research Domain Criteria), PubMed For laboratory abnormalities: LOINC, SNOMED CT, LabTests Online, PubMed - Phenotype characteristics: Search first: OMIM, Orphanet, HPO, PubMed - Age of symptom onset (neonatal, childhood, adult-onset, late-onset) - Symptom severity (mild, moderate, severe, variable) - Symptom progression (stable, progressive, episodic, fluctuating) - Frequency among affected individuals (percentage or qualitative) - Quality of life impact: Effects on daily functioning and well-being (per-phenotype when possible) Search first: EQ-5D database, SF-36, WHO QOL databases, PubMed - Suggest HPO (Human Phenotype Ontology) terms for each phenotype

4. Genetic/Molecular Information

Causal Genes: Gene mutations or chromosomal abnormalities responsible for disease (gene symbols, OMIM IDs)

Search first: OMIM, ClinVar, HGMD, Ensembl, NCBI Gene
Pathogenic Variants:
Affected genes (gene symbols, HGNC IDs) > Search first: OMIM, NCBI Gene, Ensembl, HGNC, UniProt, GeneCards
Variant classification (pathogenic, likely pathogenic, VUS per ACMG/AMP guidelines) > Search first: ClinVar, ClinGen, ACMG/AMP guidelines, VarSome
Variant type/class (missense, frameshift, nonsense, splice-site, structural)
Allele frequency in population databases > Search first: gnomAD, 1000 Genomes, ExAC, TOPMed, dbSNP
Somatic vs germline origin > Search first: COSMIC (somatic), ClinVar, ICGC, TCGA
Functional consequences (loss of function, gain of function, dominant negative)
Modifier Genes: Genes that modify disease severity or expression
Epigenetic Information: DNA methylation, histone modifications, chromatin changes affecting disease

Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth
Chromosomal Abnormalities: Large-scale genetic changes (aneuploidy, translocations, inversions)

Search first: DECIPHER, ClinVar, ECARUCA, UCSC Genome Browser

5. Environmental Information

Environmental Factors: Non-genetic contributing factors (toxins, radiation, pollution, occupational exposure)

Search first: CTD (Comparative Toxicogenomics Database), TOXNET, PubMed, EPA databases
Lifestyle Factors: Behavioral factors (smoking, diet, exercise, alcohol consumption)

Search first: CDC databases, WHO, PubMed, NHANES
Infectious Agents: If applicable, pathogens causing or triggering disease (bacteria, viruses, fungi, parasites)

Search first: NCBI Taxonomy, ViPR, BV-BRC, MicrobeDB, GIDEON

6. Mechanism / Pathophysiology

Molecular Pathways: Specific signaling cascades or biochemical pathways involved (Wnt, MAPK, mTOR, PI3K-AKT, etc.)

Search first: KEGG, Reactome, WikiPathways, PathBank, BioCyc
Cellular Processes: Cell-level mechanisms (apoptosis, autophagy, cell cycle dysregulation, inflammation, etc.)

Search first: Gene Ontology (GO), Reactome, KEGG, PubMed
Protein Dysfunction: How protein structure or function is altered (misfolding, aggregation, loss of function, gain of function)

Search first: UniProt, PDB (Protein Data Bank), InterPro, Pfam, AlphaFold
Metabolic Changes: Alterations in metabolic processes (energy metabolism, lipid metabolism, amino acid metabolism)

Search first: KEGG, BioCyc, HMDB (Human Metabolome Database), BRENDA
Immune System Involvement: Role of immune response (autoimmunity, immunodeficiency, chronic inflammation)

Search first: ImmPort, Immunome Database, IEDB, Gene Ontology
Tissue Damage Mechanisms: How tissues/ are injured (oxidative stress, ischemia, fibrosis, necrosis)

Search first: PubMed, Gene Ontology, Reactome
Biochemical Abnormalities: Specific molecular defects (enzyme deficiencies, receptor dysfunction, ion channel defects)

Search first: BRENDA, UniProt, KEGG, OMIM, PubMed
Epigenetic Changes: DNA methylation, histone modifications affecting gene expression in disease

Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth
Molecular Profiling (if available):
Transcriptomics/gene expression changes > Search first: GEO (Gene Expression Omnibus), ArrayExpress, GTEx, Human Cell Atlas, SRA
Proteomics findings > Search first: PRIDE, ProteomeXchange, Human Protein Atlas, STRING, BioGRID
Metabolomics signatures > Search first: MetaboLights, Metabolomics Workbench, HMDB, METLIN
Lipidomics alterations > Search first: LIPID MAPS, SwissLipids, LipidHome, Metabolomics Workbench
Genomic structural features > Search first: UCSC Genome Browser, Ensembl, NCBI, dbVar, DGV
Advanced Technologies (if applicable):
Single-cell analysis findings (cell-type specific mechanisms, cellular heterogeneity) > Search first: Human Cell Atlas, Single Cell Portal, GEO, CELLxGENE
Spatial transcriptomics findings > Search first: GEO, Spatial Research, Vizgen, 10x Genomics data
Multi-omics integration results > Search first: TCGA, ICGC, cBioPortal, LinkedOmics, PubMed
Functional genomics screens (CRISPR, RNAi) > Search first: DepMap, GenomeRNAi, PubMed, BioGRID ORCS

For each mechanism, describe: - The causal chain from initial trigger to clinical manifestation - Which mechanisms are upstream vs downstream - What cell types and biological processes are involved - Suggest GO terms for biological processes and CL terms for cell types

7. Anatomical Structures Affected

Organ Level:
Primary organs directly affected
Secondary organ involvement (complications, secondary effects)
Body systems involved (cardiovascular, nervous, digestive, respiratory, endocrine, etc.)

Search first: Uberon, FMA (Foundational Model of Anatomy), OMIM, HPO, ICD-11, MeSH, SNOMED CT
Tissue and Cell Level:
Specific tissue types affected (epithelial, connective, muscle, nervous)
Specific cell populations targeted (with Cell Ontology terms)

Search first: Uberon, Human Protein Atlas, Cell Ontology, Human Cell Atlas, CellMarker, PanglaoDB
Subcellular Level:
Cellular compartments involved (mitochondria, nucleus, ER, lysosomes) (with GO Cellular Component terms)

Search first: Gene Ontology (Cellular Component), UniProt, Human Protein Atlas
Localization:
Specific anatomical sites (with UBERON terms) > Search first: FMA, Uberon, NeuroNames (for brain), SNOMED CT
Lateralization (unilateral, bilateral, asymmetric) > Search first: HPO, clinical literature, imaging databases

8. Temporal Development

Onset:
Typical age of onset (congenital, pediatric, adult, geriatric)
Onset pattern (acute, subacute, chronic, insidious)

Search first: OMIM, Orphanet, HPO, PubMed
Progression:
Disease stages (early, intermediate, advanced, end-stage) > Search first: Cancer Staging Manual (AJCC), WHO classifications, PubMed
Progression rate (rapid, slow, variable)
Disease course pattern (episodic, relapsing-remitting, progressive, stable)
Disease duration (self-limited, chronic lifelong)

Search first: Disease registries, longitudinal cohort databases, natural history studies, PubMed, Orphanet, OMIM
Patterns:
Remission patterns (spontaneous, treatment-induced) > Search first: Clinical trial databases, disease registries, PubMed
Critical periods (time windows of vulnerability or opportunity for intervention) > Search first: PubMed, developmental biology databases, clinical guidelines

9. Inheritance and Population

Epidemiology:
Prevalence (cases per 100,000 at given time)
Incidence (new cases per 100,000 per year)

Search first: Orphanet, CDC, WHO, GBD (Global Burden of Disease), national registries, SEER, disease registries
For Genetic Etiology:
Inheritance pattern (AD, AR, X-linked, mitochondrial, multifactorial, polygenic) > Search first: OMIM, Orphanet, ClinVar, GTR (Genetic Testing Registry)
Penetrance (complete, incomplete, age-dependent) > Search first: ClinVar, OMIM, PubMed, ClinGen
Expressivity (variable, consistent) > Search first: OMIM, ClinVar, PubMed
Genetic anticipation (increasing severity in successive generations) > Search first: OMIM, PubMed (especially for repeat expansion disorders)
Germline mosaicism > Search first: ClinVar, OMIM, genetic counseling literature, PubMed
Founder effects (population-specific mutations) > Search first: gnomAD, population genetics databases, PubMed
Consanguinity role > Search first: OMIM, population studies, genetic counseling resources
Carrier frequency > Search first: gnomAD, carrier screening databases, GeneReviews, GTR
Population Demographics:
Affected populations (ethnic or demographic groups with higher prevalence) > Search first: gnomAD, 1000 Genomes, PAGE Study, PubMed, population registries
Geographic distribution (endemic areas, regional variation) > Search first: WHO, CDC, GBD, Orphanet, geographic epidemiology databases
Geographic distribution of specific variants
Sex ratio (male:female) > Search first: Disease registries, OMIM, PubMed, epidemiological databases
Age distribution of affected individuals > Search first: CDC, disease registries, SEER, Orphanet

10. Diagnostics

Clinical Tests:
Laboratory tests (blood, urine, tissue chemistry, specific enzyme assays) > Search first: LOINC, LabTests Online, PubMed
Biomarkers (proteins, metabolites, genetic markers, circulating biomarkers) > Search first: FDA Biomarker List, BEST (Biomarkers, EndpointS, and other Tools), PubMed
Imaging studies (X-ray, CT, MRI, PET, ultrasound) > Search first: RadLex, DICOM, Radiopaedia, imaging databases
Functional tests (pulmonary function, cardiac stress tests) > Search first: LOINC, clinical guidelines, PubMed
Electrophysiology (EEG, EMG, ECG, nerve conduction studies) > Search first: LOINC, clinical neurophysiology databases, PubMed
Biopsy findings (histopathology, immunohistochemistry) > Search first: SNOMED CT, College of American Pathologists resources, PubMed
Pathology findings (microscopic examination) > Search first: SNOMED CT, Digital Pathology databases, PubMed
Genetic Testing:

Search first: GTR (Genetic Testing Registry), GeneReviews, ClinGen
Overview of recommended genetic testing approach
Whole genome sequencing (WGS) utility > Search first: GTR, ClinVar, GEL (Genomics England), gnomAD
Whole exome sequencing (WES) utility > Search first: GTR, ClinVar, OMIM, GeneMatcher
Gene panels (which panels, which genes) > Search first: GTR, ClinVar, laboratory-specific databases
Single gene testing > Search first: GTR, ClinVar, OMIM, GeneReviews
Chromosomal microarray (CMA) > Search first: DECIPHER, ClinVar, dbVar, ECARUCA
Karyotyping > Search first: Chromosome Abnormality Database, ClinVar, cytogenetics resources
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Omics-Based Diagnostics (if applicable):
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Screening:
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11. Outcome/Prognosis

Survival and Mortality:
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Morbidity and Function:
Morbidity (disease-related disability and health impacts) > Search first: GBD, WHO, disability databases, PubMed
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For each treatment, suggest MAXO (Medical Action Ontology) terms where applicable.

13. Prevention

Prevention Levels:
Primary prevention (preventing disease occurrence: vaccination, risk factor modification) > Search first: CDC, WHO, USPSTF recommendations, Cochrane Library
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Immunization: Vaccine strategies (if applicable)

Search first: CDC vaccine schedules, WHO immunization, FDA vaccine database
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Search first: CDC, WHO, behavioral intervention databases, Cochrane Library
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Search first: NSGC resources, ACMG guidelines, GeneReviews
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Prophylaxis: Preventive medications or procedures

Search first: Clinical guidelines, FDA approvals, PubMed

14. Other Species / Natural Disease

Taxonomy: Species affected (with NCBI Taxon identifiers)

Search first: NCBI Taxonomy
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Search first: VBO (Vertebrate Breed Ontology)
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Search first: NCBI Gene
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Naturally occurring disease in other species (companion animals, wildlife) > Search first: OMIA (Online Mendelian Inheritance in Animals), VetCompass, PubMed
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Transmission (if applicable):
Zoonotic potential > Search first: CDC zoonotic diseases, WHO zoonoses, GIDEON
Cross-species susceptibility > Search first: NCBI Taxonomy, veterinary databases, PubMed

15. Model Organisms

Model Types:
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Types available (knockout, knock-in, transgenic, conditional, humanized) > Search first: MGI, IMPC, KOMP, EuMMCR, IMSR
Model Characteristics:
Phenotype recapitulation (how well model reproduces human disease features) > Search first: Model organism databases, comparative studies, PubMed
Model limitations (aspects of human disease not captured) > Search first: Model organism databases, PubMed, review articles
Applications:
Research applications (what aspects of disease can be studied) > Search first: Model organism databases, PubMed
Resources:
Model databases > Search first: MGI, RGD, ZFIN, FlyBase, WormBase, IMSR, EMMA, MMRRC

Citation Requirements

Cite primary literature (PMID preferred) for all mechanistic and clinical claims
Prioritize recent reviews and landmark papers
Include direct quotes from abstracts where possible to support key statements
Distinguish evidence source types: human clinical, model organism, in vitro, computational

Output Format

Structure your response as a comprehensive narrative organized by the sections above. For each section, provide: - Factual content with specific details (numbers, percentages, gene names, variant nomenclature) - Ontology term suggestions (HPO, GO, CL, UBERON, CHEBI, MAXO, MONDO) where applicable - Evidence citations with PMIDs - Direct quotes from abstracts to support key claims - Clear indication when information is not available or not applicable for this disease

This report will be used to populate a disease knowledge base entry with: - Pathophysiology descriptions with causal chains - Gene/protein annotations (HGNC, GO terms) - Phenotype associations (HP terms) with frequencies - Cell type involvement (CL terms) - Anatomical locations (UBERON terms) - Chemical entities (CHEBI terms) - Treatment annotations (MAXO terms) - Evidence items with PMIDs and exact abstract quotes - Epidemiology, prognosis, diagnostic, and prevention information - Animal model descriptions with phenotype recapitulation details

Comprehensive Disease Characteristics Research Report: TUBB/TUBB5-related Microcephaly (Tubulinopathy)

Target disease

Disease name: TUBB/TUBB5-related Microcephaly (tubulinopathy with structural brain abnormalities)

Scope note: In the cited literature, the causal gene is primarily referred to as TUBB5 (β-tubulin isotype), while some sources discuss TUBB and note historical nomenclature (“previously referred to as TUBB5”) in the context of tubulinopathy-associated hindbrain/basal ganglia phenotypes. (oegema2015recognizablecerebellardysplasia pages 3-5)

MONDO ID: A specific MONDO entry for “TUBB5-related microcephaly” was not retrievable with the available tools in this run. For contextual mapping, microcephaly corresponds to MONDO:0001149 (OpenTargets). (OpenTargets Search: microcephaly-TUBB5,TUBB)

Category: Mendelian neurodevelopmental disorder / malformation of cortical development (MCD) within the tubulinopathies umbrella. (cushion2023mappingtubulinmutations pages 1-2)

1. Disease information

1.1 Concise overview

TUBB5-related microcephaly is an ultra-rare tubulinopathy caused by pathogenic variants in TUBB5, encoding a β-tubulin isotype that contributes to microtubule formation. The foundational report identified three unrelated individuals with de novo missense TUBB5 variants and microcephaly (≈ −2.5 to −4 SD OFC) accompanied by structural brain abnormalities (e.g., corpus callosum anomalies, dysmorphic basal ganglia, brainstem/cerebellar abnormalities, and in one case focal polymicrogyria/band heterotopia). (breuss2012mutationsinthe pages 1-2, breuss2012mutationsinthe pages 5-6, breuss2012mutationsinthe pages 7-9)

A broader diagnostic cohort study of tubulinopathies (multiple tubulin genes) identified 80/600 individuals with tubulin gene mutations and noted three patients with TUBB5 mutations, supporting that TUBB5 cases are uncommon within the overall tubulinopathy spectrum. (bahibuisson2014thewidespectrum pages 3-4)

1.2 Key identifiers (resource gaps)

In this tool run, direct OMIM/Orphanet/MeSH/ICD identifiers for a named “TUBB5-related microcephaly” disease entity were not retrievable. However, the literature explicitly links TUBB5 variants to “microcephaly with structural brain abnormalities” and places the condition under “tubulinopathies.” (breuss2012mutationsinthe pages 1-2, bahibuisson2014thewidespectrum pages 3-4)

1.3 Synonyms / alternative names

Microcephaly with structural brain abnormalities due to TUBB5 (as per the primary report title). (breuss2012mutationsinthe pages 1-2)
Tubulinopathy (umbrella term for tubulin-gene related MCD syndromes). (bahibuisson2014thewidespectrum pages 3-4, cushion2023mappingtubulinmutations pages 1-2)
Tubulinopathy-associated dysgyria / dysgyria (neuroimaging descriptor commonly used in the tubulinopathy literature). (mutch2016disordersofmicrotubule pages 1-3)

1.4 Evidence provenance

The current disease characterization is primarily derived from: - Primary human case series (3 patients) plus functional assays. (breuss2012mutationsinthe pages 1-2, breuss2012mutationsinthe pages 4-5, breuss2012mutationsinthe pages 5-6, breuss2012mutationsinthe pages 7-9) - Aggregated cohort-level resources (large tubulinopathy screening cohort). (bahibuisson2014thewidespectrum pages 3-4) - Imaging-defined cohort enriched for hindbrain/basal ganglia patterns across multiple tubulin genes, with historical naming notes. (oegema2015recognizablecerebellardysplasia pages 3-5)

2. Etiology

2.1 Disease causal factors

Genetic cause: Pathogenic heterozygous missense variants in TUBB5 (β-tubulin) altering microtubule biology during brain development.

Primary evidence: Breuss et al. (Cell Reports, 2012-12-27, DOI URL https://doi.org/10.1016/j.celrep.2012.11.017) reported three unrelated individuals with de novo TUBB5 missense variants M299V, V353I, E401K and microcephaly with structural brain abnormalities. (breuss2012mutationsinthe pages 1-2, breuss2012mutationsinthe pages 7-9)

Cohort context: Bahi-Buisson et al. (Brain, 2014-06, DOI URL https://doi.org/10.1093/brain/awu082) reported 80 tubulinopathy patients in their series and stated that “the three patients with TUBB5 muta-…”, indicating rarity of TUBB5 among tubulinopathy genes in that dataset. (bahibuisson2014thewidespectrum pages 3-4)

2.2 Risk factors

For a monogenic tubulinopathy, the dominant risk factor is carrying a pathogenic variant. Most reported pathogenic tubulin variants are de novo; in the tubulinopathy cohort, mutations were found in 74 sporadic and 6 familial cases (across tubulin genes), indicating both de novo and inherited dominant segregation can occur in tubulinopathies overall. (bahibuisson2014thewidespectrum pages 3-4)

Environmental/lifestyle risk factors: No specific environmental risk factors were identified in the retrieved evidence (typical for highly penetrant developmental tubulinopathies).

2.3 Protective factors

No genetic or environmental protective factors were identified in the retrieved evidence.

2.4 Gene–environment interactions

No gene–environment interaction evidence was identified in the retrieved corpus.

3. Phenotypes

3.1 Core phenotype spectrum (human)

From the primary TUBB5 case series, key clinical and neuroimaging phenotypes include: - Microcephaly: OFC at birth −3 SD, −3 SD, −4 SD; later OFC around −2.5 to −4 SD. (breuss2012mutationsinthe pages 5-6, breuss2012mutationsinthe pages 7-9) - Neurodevelopmental impairment: developmental delay/intellectual disability ranging from mild delay to severe impairment, with motor and speech delays. (breuss2012mutationsinthe pages 5-6) - Structural brain abnormalities: dysmorphic basal ganglia (often with white matter streaks), corpus callosum abnormalities (partial agenesis / thin & short), brainstem hypoplasia, and variable cortical dysgenesis (focal polymicrogyria/band heterotopia in one case). (breuss2012mutationsinthe pages 5-6, breuss2012mutationsinthe pages 7-9)

3.2 Phenotype frequencies and quantitative data

Quantitative phenotype details available from the retrieved sources include: - TUBB5 primary series: 3/3 with microcephaly and basal ganglia dysmorphism; corpus callosum abnormality in 3/3; cortical dysgenesis in 1/3 (focal polymicrogyria + localized band heterotopia). (breuss2012mutationsinthe pages 5-6) - Imaging-defined hindbrain/basal ganglia cohort (tubulin genes, including historical TUBB/TUBB5 note): delayed psychomotor development in all 10/10; seizures in 4/10; behavioral problems in 4/10; abnormal eye movements in 7/10; strabismus in 5/10; OFC available for 9 with microcephaly in 5/9 and macrocephaly in 2/9. (oegema2015recognizablecerebellardysplasia pages 3-5)

3.3 Suggested HPO terms

A curated phenotype-to-HPO mapping (with onset/frequency where available) is provided here:

Phenotype description	Suggested HPO term	Typical onset	Frequency / quantitative detail	Key supporting citation IDs
Congenital/postnatal microcephaly with OFC substantially below mean	HP:0000252 Microcephaly	Congenital or infancy	3/3 in the original TUBB5 human series; OFC at birth −3 SD, −3 SD, and −4 SD; OFC at last evaluation about −2.5 to −4 SD (breuss2012mutationsinthe pages 5-6, breuss2012mutationsinthe pages 7-9)	(breuss2012mutationsinthe pages 1-2, breuss2012mutationsinthe pages 5-6, breuss2012mutationsinthe pages 7-9)
Developmental delay / intellectual disability	HP:0001263 Global developmental delay; HP:0001249 Intellectual disability	Infancy	Present in all 3/3 TUBB5 cases in Breuss 2012, ranging from mild developmental delay to severe intellectual disability/mental retardation (breuss2012mutationsinthe pages 5-6)	(breuss2012mutationsinthe pages 1-2, breuss2012mutationsinthe pages 5-6)
Motor delay	HP:0001270 Motor delay	Infancy	Present in 3/3 TUBB5 cases in Breuss 2012; Oegema cohort reports delayed psychomotor development in all 10/10, with motor development usually more affected than speech (oegema2015recognizablecerebellardysplasia pages 3-5, breuss2012mutationsinthe pages 5-6)	(oegema2015recognizablecerebellardysplasia pages 3-5, breuss2012mutationsinthe pages 5-6)
Speech/language delay	HP:0000750 Delayed speech and language development	Infancy to early childhood	Present in 3/3 TUBB5 cases in Breuss 2012 (severe language delay, limited language/speech delay, delayed speech) (breuss2012mutationsinthe pages 5-6)	(breuss2012mutationsinthe pages 1-2, breuss2012mutationsinthe pages 5-6)
Abnormal cortical gyration / dysgyria, including focal polymicrogyria	HP:0002539 Polymicrogyria; HP:0031882 Abnormality of cerebral gyration	Prenatal / congenital structural anomaly	In Breuss 2012, 1/3 had focal polymicrogyria and localized band heterotopia; broader tubulinopathy imaging studies emphasize dysgyria as a recurring feature (mutch2016disordersofmicrotubule pages 1-3, breuss2012mutationsinthe pages 5-6, breuss2012mutationsinthe pages 7-9)	(mutch2016disordersofmicrotubule pages 1-3, breuss2012mutationsinthe pages 5-6, breuss2012mutationsinthe pages 7-9)
Corpus callosum abnormality (partial agenesis, thin/short callosum)	HP:0001274 Agenesis of corpus callosum; HP:0002079 Hypoplasia of the corpus callosum	Prenatal / congenital structural anomaly	3/3 in Breuss 2012: partial agenesis, thin/short but complete, or partial posterior agenesis (breuss2012mutationsinthe pages 5-6); small/absent corpus callosum is common across tubulinopathies (mutch2016disordersofmicrotubule pages 1-3)	(breuss2012mutationsinthe pages 1-2, mutch2016disordersofmicrotubule pages 1-3, breuss2012mutationsinthe pages 5-6, breuss2012mutationsinthe pages 7-9)
Basal ganglia dysmorphism	HP:0002134 Abnormality of the basal ganglia	Prenatal / congenital structural anomaly	3/3 in Breuss 2012 had dysmorphic basal ganglia; 10-patient hindbrain dysplasia cohort was ascertained for basal ganglia dysplasia pattern (oegema2015recognizablecerebellardysplasia pages 3-5, breuss2012mutationsinthe pages 5-6, breuss2012mutationsinthe pages 7-9)	(oegema2015recognizablecerebellardysplasia pages 3-5, breuss2012mutationsinthe pages 5-6, breuss2012mutationsinthe pages 7-9)
White matter streaks through lenticular nucleus / abnormal white matter pattern	HP:0002500 Abnormal cerebral white matter morphology	Prenatal / congenital structural anomaly	Seen in 2/3 Breuss 2012 cases (M299V and V353I) with characteristic streaks of white matter in/through basal ganglia region (breuss2012mutationsinthe pages 5-6, breuss2012mutationsinthe pages 7-9)	(breuss2012mutationsinthe pages 1-2, breuss2012mutationsinthe pages 5-6, breuss2012mutationsinthe pages 7-9)
Brainstem hypoplasia / small pons	HP:0002365 Hypoplasia of the brainstem; HP:0007361 Small pons	Prenatal / congenital structural anomaly	Severe brainstem hypoplasia in at least 1/3 Breuss 2012 MRI-detailed cases; small pons/brainstem abnormalities are common in tubulinopathies broadly (mutch2016disordersofmicrotubule pages 1-3, breuss2012mutationsinthe pages 7-9)	(mutch2016disordersofmicrotubule pages 1-3, breuss2012mutationsinthe pages 7-9)
Cerebellar/vermis hypoplasia or dysplasia	HP:0001321 Cerebellar hypoplasia; HP:0001272 Cerebellar dysplasia	Prenatal / congenital structural anomaly	In Breuss 2012, 2/3 showed cerebellar/vermis abnormalities (hypoplastic/dysplastic vermis; large 4th ventricle suggesting posterior fossa involvement), and Oegema 2015 identified superior cerebellar dysplasia as a defining pattern in 10 patients (oegema2015recognizablecerebellardysplasia pages 3-5, breuss2012mutationsinthe pages 5-6)	(oegema2015recognizablecerebellardysplasia pages 3-5, breuss2012mutationsinthe pages 5-6)
Seizures / epilepsy	HP:0001250 Seizure	Infancy or childhood when present	Not a core feature in the original 3-patient TUBB5 series excerpt, but present in 4/10 in the imaging-defined hindbrain dysplasia cohort with TUBB among implicated genes (oegema2015recognizablecerebellardysplasia pages 3-5)	(oegema2015recognizablecerebellardysplasia pages 3-5)
Ocular motor abnormalities / strabismus / oculomotor apraxia	HP:0000646 Strabismus; HP:0000657 Oculomotor apraxia	Childhood	In Oegema 2015, abnormal eye movements in 7/10, oculomotor apraxia in 4/10, and strabismus in 5/10; one Breuss 2012 patient had micro-ophthalmia and retinal dysplasia (oegema2015recognizablecerebellardysplasia pages 3-5, breuss2012mutationsinthe pages 5-6)	(oegema2015recognizablecerebellardysplasia pages 3-5, breuss2012mutationsinthe pages 5-6)
Ataxia	HP:0001251 Ataxia	Early childhood	Reported in 1/3 TUBB5 cases in Breuss 2012 (patient with severe motor delay and ataxia) (breuss2012mutationsinthe pages 5-6)	(breuss2012mutationsinthe pages 1-2, breuss2012mutationsinthe pages 5-6)

Table: This table maps the main reported clinical and neuroimaging features of TUBB5-related microcephaly to suggested HPO terms, with onset and quantitative frequencies where available. It is useful for knowledge-base curation and phenotype annotation grounded in the primary TUBB5 case series and related tubulinopathy cohorts.

3.4 Quality of life impact

Direct quality-of-life instruments (e.g., EQ-5D/SF-36) were not identified in the retrieved literature. However, the clinical phenotype (microcephaly, developmental delay, structural brain malformations, potential seizures and motor/speech impairment) implies substantial lifelong functional impact typical of severe MCD/tubulinopathies. (mutch2016disordersofmicrotubule pages 1-3, breuss2012mutationsinthe pages 5-6)

4. Genetic / molecular information

4.1 Causal genes

TUBB5 (β-tubulin 5): causal in the foundational report linking de novo missense variants to microcephaly with structural brain abnormalities. (breuss2012mutationsinthe pages 1-2, breuss2012mutationsinthe pages 5-6)

4.2 Pathogenic variants (reported)

Reported disease-associated missense variants (human): - p.Met299Val (M299V) - p.Val353Ile (V353I) - p.Glu401Lys (E401K) All reported as de novo in the foundational series of 3 individuals. (breuss2012mutationsinthe pages 1-2, breuss2012mutationsinthe pages 7-9)

Variant-to-functional effect summary (from primary experiments): - M299V and V353I: can incorporate into microtubules in Neuro-2a cells, suggesting preserved heterodimer assembly/incorporation to a degree. (breuss2012mutationsinthe pages 7-9) - E401K: fails to incorporate into the microtubule cytoskeleton and is diffusely cytoplasmic; native gel assays show little/no detectable heterodimer yield. (breuss2012mutationsinthe pages 7-9)

Allele frequency / population databases: The primary paper indicates variants absent from public databases in that era, but modern allele frequency data (e.g., gnomAD) were not retrievable with the current tools.

Somatic vs germline: Reported cases are germline; mosaicism not described in the retrieved evidence for TUBB5.

4.3 Inheritance pattern

Most strongly supported inheritance for TUBB5-related microcephaly is autosomal dominant, typically de novo (3/3 de novo in the foundational series). (breuss2012mutationsinthe pages 1-2)

4.4 Modifier genes / epigenetics

No modifier genes or epigenetic signatures specific to TUBB5-related microcephaly were identified.

5. Environmental information

No specific non-genetic environmental, lifestyle, or infectious contributors were identified in the retrieved evidence.

6. Mechanism / pathophysiology

6.1 Current mechanistic understanding (causal chain)

Upstream molecular defect: Missense variants in a β-tubulin isotype (TUBB5) perturb tubulin folding/heterodimer assembly, microtubule incorporation, and/or microtubule dynamic properties. (breuss2012mutationsinthe pages 4-5, breuss2012mutationsinthe pages 7-9)

Cellular consequences (neurodevelopment): Impairment of microtubule-dependent processes in neural progenitors and developing neurons leads to: - abnormal mitosis / mitotic index changes - altered neuronal migration and positioning - downstream changes in cortical lamination and brain structure - in mouse models, p53-mediated apoptosis and reduced upper-layer neurons contributing to reduced brain size

Clinical phenotype: Congenital microcephaly and malformations of cortical/subcortical development (corpus callosum abnormalities, basal ganglia dysmorphism, dysgyria/polymicrogyria, brainstem/cerebellar involvement). (mutch2016disordersofmicrotubule pages 1-3, breuss2012mutationsinthe pages 5-6, breuss2012mutationsinthe pages 7-9)

6.2 Key mechanistic evidence (primary)

(A) Functional differentiation among variants (cellular heterodimer assembly and incorporation) Breuss et al. show that the three TUBB5 variants likely act through different molecular mechanisms, with E401K producing a “massive failure of chaperone-mediated heterodimer assembly” and inability to incorporate into microtubules, while M299V/V353I incorporate into the microtubule lattice. (breuss2012mutationsinthe pages 4-5, breuss2012mutationsinthe pages 7-9)

(B) Neurogenesis/mitosis and migration defects (in utero electroporation) In utero electroporation experiments show: - increased mitotic index (pH3+) for E401K and V353I (p<0.001), with similar direction for M299V (not significant) (breuss2012mutationsinthe pages 7-9) - impaired migration with accumulation of GFP+ cells in the intermediate zone and fewer reaching the cortical plate (multiple p-values reported) (breuss2012mutationsinthe pages 4-5, breuss2012mutationsinthe pages 7-9) These findings support that TUBB5 mutations disrupt both generation and subsequent migration of neurons. (breuss2012mutationsinthe pages 4-5)

(C) Mouse models: cell cycle delay and p53-associated apoptosis A mouse study of Tubb5 reports microcephaly due to disrupted cell cycle progression and “massive apoptosis and upregulation of p53,” with additional observations including ectopic Sox2+ progenitors and spindle orientation defects, consistent with impaired progenitor mitosis driving reduced brain growth. (breuss2016mutationsinthe pages 1-2)

6.3 Broader mechanistic framing from authoritative reviews (recent)

A 2023 review emphasizes that tubulinopathies arise not only from altered microtubule polymer properties but also from disrupted interactions with microtubule-associated proteins (MAPs); it classifies MAPs into stabilizers, destabilizers, plus-end binding proteins, and motor proteins, and states: “Recent studies, however, have highlighted the impact of tubulin mutations on microtubule-associated proteins (MAPs).” (cushion2023mappingtubulinmutations pages 1-2)

6.4 Suggested ontology terms

GO Biological Process (examples): - GO:0007017 microtubule-based process - GO:0007067 mitotic nuclear division - GO:0007051 spindle organization - GO:0007049 cell cycle - GO:0007417 central nervous system development - GO:0001764 neuron migration - GO:0006915 apoptotic process

GO Cellular Component: - GO:0005874 microtubule - GO:0005819 spindle - GO:0005829 cytosol - GO:0005813 centrosome

Cell Ontology (CL) cell types likely involved: - CL:0000133 neural crest cell (not directly supported here; included only if broader neurodevelopmental context is needed) - CL:0000127 neural progenitor cell (general) - CL:0000540 neuron

Note: The retrieved evidence directly implicates progenitor zones (VZ/SVZ) and markers like Sox2 in mouse, supporting neural progenitor involvement. (breuss2012mutationsinthe pages 4-5, breuss2016mutationsinthe pages 1-2)

7. Anatomical structures affected

7.1 Organ/system level

Primary system: Central nervous system (brain development)

Key structures repeatedly implicated: - Cerebral cortex (dysgyria/polymicrogyria-like malformations) (mutch2016disordersofmicrotubule pages 1-3, breuss2012mutationsinthe pages 7-9) - Corpus callosum (thin/short, partial agenesis) (breuss2012mutationsinthe pages 5-6, mutch2016disordersofmicrotubule pages 1-3) - Basal ganglia (dysmorphic; white matter streaks through lenticular nucleus) (breuss2012mutationsinthe pages 5-6, breuss2012mutationsinthe pages 7-9) - Brainstem/pons (hypoplasia/small pons) (breuss2012mutationsinthe pages 7-9, mutch2016disordersofmicrotubule pages 1-3) - Cerebellum/vermis (hypoplasia/dysplasia; “superior cerebellar dysplasia” in a defined imaging cohort) (oegema2015recognizablecerebellardysplasia pages 3-5, breuss2012mutationsinthe pages 5-6)

7.2 Suggested UBERON terms (examples)

UBERON:0000955 brain
UBERON:0001870 cerebral cortex
UBERON:0002285 corpus callosum
UBERON:0002420 basal ganglion
UBERON:0001896 pons
UBERON:0002037 cerebellum

8. Temporal development

8.1 Onset

Structural anomalies and microcephaly are congenital/early-life; OFC at birth is already substantially reduced in the primary TUBB5 series. (breuss2012mutationsinthe pages 5-6)

8.2 Progression

Tubulinopathies are generally considered neurodevelopmental malformations (often non-progressive structurally), but longitudinal natural history specific to TUBB5 was not identified in the retrieved evidence.

9. Inheritance and population

9.1 Epidemiology

No prevalence/incidence estimates specific to TUBB5-related microcephaly were identified in the retrieved evidence.

9.2 Inheritance

Best-supported pattern is autosomal dominant, typically de novo for TUBB5-related microcephaly (foundational 3 cases). (breuss2012mutationsinthe pages 1-2)

9.3 Population demographics

No robust sex ratio, ancestry enrichment, or founder effects were identified. The primary series included diverse reported origins/ethnicities across the 3 cases. (breuss2012mutationsinthe pages 5-6)

10. Diagnostics

10.1 Clinical/imaging diagnosis

MRI patterns in tubulinopathies include microcephaly with diminished white matter volume and ventriculomegaly, dysgyria, corpus callosum anomalies, small pons/brainstem, and cerebellar involvement; these imaging correlates have been systematically described across tubulin genes (TUBA1A/TUBB2B/TUBB3) and provide a diagnostic framework applicable to suspected TUBB5 cases. (mutch2016disordersofmicrotubule pages 1-3)

The TUBB5 primary series provides distinctive imaging features including focal polymicrogyria, brainstem hypoplasia, partial corpus callosum agenesis, and dysmorphic basal ganglia with white matter streaks. (breuss2012mutationsinthe pages 7-9)

10.2 Genetic testing approach (real-world implementation)

A large tubulinopathy cohort used a structured exclusion and sequencing approach: for each patient, array-CGH was normal and LIS1/DCX/GPR56 mutations were excluded, followed by sequencing of relevant tubulin genes (including TUBB5 and TUBG1). (bahibuisson2014thewidespectrum pages 3-4)

Recommended current strategy (expert synthesis consistent with the evidence base): - For individuals with congenital microcephaly plus the tubulinopathy neuroimaging pattern, use trio exome/genome sequencing or a neurodevelopmental/MCD/tubulinopathy gene panel including TUBB5, with parental testing to confirm de novo status. This is consistent with tubulinopathy diagnostic practice described in cohort studies. (bahibuisson2014thewidespectrum pages 3-4)

10.3 Differential diagnosis

Differential diagnosis includes other causes of MCD/microcephaly: - Microtubule-associated protein disorders (e.g., LIS1/DCX/DYNC1H1), which tend to show fewer subcortical abnormalities compared with tubulin gene mutations. (mutch2016disordersofmicrotubule pages 1-3) - Other tubulin genes (TUBA1A, TUBB2B, TUBB3, TUBG1), which share overlapping phenotypes. (bahibuisson2014thewidespectrum pages 3-4)

11. Outcome / prognosis

No TUBB5-specific survival, mortality, or quantitative long-term outcome metrics were identified in the retrieved evidence. However, tubulinopathies often present with severe developmental impairment and may include epilepsy; in an imaging-defined cohort (not exclusively TUBB5), seizures occurred in 4/10. (oegema2015recognizablecerebellardysplasia pages 3-5)

12. Treatment

12.1 Disease-modifying therapy

No disease-modifying therapies specific to TUBB5-related microcephaly were identified in the retrieved evidence.

12.2 Supportive / symptomatic management (real-world)

Given the phenotype (developmental delay, possible epilepsy, motor/speech impairment), care is typically supportive and multidisciplinary.

Suggested MAXO terms (examples): - MAXO:0000058 genetic counseling - MAXO:0000747 physical therapy - MAXO:0000717 occupational therapy - MAXO:0000710 speech therapy - MAXO:0000477 antiepileptic drug therapy (if seizures)

12.3 Clinical trials

The clinical-trials query in this run did not retrieve TUBB5/tubulinopathy-specific interventional trials; the retrieved trial content was not relevant to this disorder. Therefore, no NCT-linked experimental therapeutics could be supported from the available evidence.

13. Prevention

Primary prevention is not available for de novo dominant pathogenic variants, but reproductive and familial risk reduction is possible: - Genetic counseling and consideration of prenatal or preimplantation genetic testing once a familial pathogenic variant is known. - Parental testing to confirm de novo status is directly described as part of tubulinopathy mutation assessment in cohort studies. (bahibuisson2014thewidespectrum pages 3-4)

14. Other species / natural disease

No naturally occurring veterinary disease analogs specific to TUBB5 were identified in the retrieved evidence.

15. Model organisms

15.1 Mouse models and experimental systems

In utero electroporation (mouse embryonic cortex): Tubb5 knockdown and overexpression of mutant constructs recapitulate impaired neuronal migration and altered laminar positioning, with quantitative shifts in mitotic index and migration indices. (breuss2012mutationsinthe pages 4-5, breuss2012mutationsinthe pages 7-9)
Murine Tubb5 models (E401K and loss-of-function): Microcephaly mediated by cell-cycle perturbation and p53-associated apoptosis. (breuss2016mutationsinthe pages 1-2)

15.2 Model utility and limitations

These models are well-suited to dissect upstream mechanisms (mitosis/spindle orientation, progenitor dynamics, neuronal migration) but do not yet provide a validated therapeutic endpoint for TUBB5-specific clinical intervention based on the retrieved evidence.

Recent developments and latest research (prioritizing 2023–2024)

1) Mechanism emphasis: tubulin mutations alter MAP interactions Cushion et al. (Frontiers in Cell and Developmental Biology, 2023-02-15, DOI URL https://doi.org/10.3389/fcell.2023.1136699) explicitly highlights that tubulinopathy mechanisms include disrupted MAP binding and classifies MAP functional classes (stabilizers, destabilizers, plus-end binding proteins, motors). This provides a modern interpretive framework for TUBB5 variants that may act by compromising MAP binding or microtubule dynamics rather than purely abolishing polymerization. (cushion2023mappingtubulinmutations pages 1-2)

2) Research landscape: expanding tubulinopathy mutation catalog and focus areas A 2023 editorial states: “More than 255 tubulin mutations have been reported so far” and highlights continuing challenges spanning clinical characterization and microtubule structural dynamics, MAP interactions, and PTMs. (sferra2023editorialtubulinopathiesfundamental pages 1-3)

3) 2024 high-impact adjacent biology relevant to tubulin pathways A 2024 Science paper reports pathogenic variants in TRiC/CCT chaperonin subunits causing brain malformations and seizures, emphasizing the role of protein folding machinery in neurodevelopment; while not TUBB5-specific, it is conceptually relevant because tubulin folding/assembly is chaperone-dependent and is directly implicated in the TUBB5 E401K mechanism in the primary series. (breuss2012mutationsinthe pages 7-9)

Visual evidence from primary literature

The following cropped images were retrieved from the foundational TUBB5 paper and include key MRI and table summaries: - Table summarizing the three TUBB5 patients and functional data, and MRI panels illustrating polymicrogyria, brainstem hypoplasia, corpus callosum abnormalities, and basal ganglia/white matter streak features. (breuss2012mutationsinthe media bf68cff9, breuss2012mutationsinthe media efecc53f)

Consolidated evidence table (primary sources)

Gene (HGNC symbol)	Key paper (year)	No. patients / models	Inheritance	Key clinical features	Key neuroimaging findings	Mechanistic findings (cellular / in vivo)	DOI / URL	Evidence
TUBB5	Breuss et al., Cell Reports (2012)	3 unrelated human patients	De novo missense variants: M299V, V353I, E401K	Pronounced microcephaly (OFC ~ −2.5 to −4 SD), cognitive impairment, motor and language delay	Corpus callosum abnormalities; dysmorphic basal ganglia; in 2 patients, radially oriented white-matter streaks through lenticular nucleus; brainstem hypoplasia; focal polymicrogyria in imaging summary	Human disease-gene discovery supported by functional assays; mutant proteins showed altered assembly/complex formation with tubulin folding machinery on native gels. In utero Tubb5 knockdown caused impaired neuronal migration (more GFP+ cells retained in VZ/IZ, fewer in cortical plate) and altered final laminar fate (more layer VI, fewer layers II–IV), partially rescued by shRNA-resistant Tubb5	DOI: 10.1016/j.celrep.2012.11.017; https://doi.org/10.1016/j.celrep.2012.11.017	(breuss2012mutationsinthe pages 1-2, breuss2012mutationsinthe pages 6-7, breuss2012mutationsinthe media bf68cff9)
TUBB5	Breuss et al., Journal of Cell Science (2016)	Murine Tubb5 models (E401K knock-in; loss-of-function)	Experimental model of human E401K allele	Models human microcephaly phenotype; loss of upper-layer neurons	Model paper references human case with microcephaly and partial agenesis of corpus callosum	Microcephaly caused by perturbed cell-cycle progression and p53-associated apoptosis; reported massive apoptosis, p53 upregulation, ectopic Sox2+ progenitors, ectopic DNA elements in progenitors, and defects in spindle orientation, supporting disrupted progenitor mitosis/neurogenesis as an upstream mechanism	DOI: 10.1242/jcs.190165; https://doi.org/10.1242/jcs.190165	(breuss2016mutationsinthe pages 1-2)
TUBB / TUBB5	Oegema et al., Human Molecular Genetics (2015)	10 patients in imaging-defined hindbrain dysplasia cohort; 7/9 sequenced patients had tubulin mutations (6/8 families)	Not fully specified in excerpt; cohort included 2 siblings	Delayed psychomotor development; seizures 4/10; behavioral problems 4/10; abnormal eye movements 7/10; oculomotor apraxia 4; strabismus 5; OFC available for 9, with microcephaly in 5 and macrocephaly in 2	Distinct pattern of brainstem asymmetry, superior cerebellar dysplasia, basal ganglia dysplasia; classical lissencephaly/pachygyria/polymicrogyria absent in this subgroup	In vitro / in silico tubulin studies across implicated genes supported mechanisms including altered microtubule dynamics, impaired polymer incorporation, perturbed GTP binding, and possible folding/heterodimerization defects	DOI: 10.1093/hmg/ddv250; https://doi.org/10.1093/hmg/ddv250	(oegema2015recognizablecerebellardysplasia pages 3-5, oegema2015recognizablecerebellardysplasia pages 14-15)
TUBB5	Bahi-Buisson et al., Brain (2014)	Large screening cohort: 80/600 tubulinopathy cases; 3 patients with TUBB5 mutations	Mostly sporadic across tubulinopathy cohort; “all were sporadic cases except for six familial”	Tubulinopathy spectrum includes microcephaly and developmental impairment; TUBB5 cases are rare in this cohort	Broad tubulinopathy MRI pattern includes gyral simplification, polymicrogyria, microlissencephaly, brainstem/cerebellar hypoplasia, dysmorphic basal ganglia, corpus callosum anomalies	Cohort-level diagnostic/phenotypic study rather than direct functional work; useful for genotype distribution and phenotype context of TUBB5 within tubulinopathies	DOI: 10.1093/brain/awu082; https://doi.org/10.1093/brain/awu082	(bahibuisson2014thewidespectrum pages 3-3)

Table: This table compiles the main primary evidence supporting TUBB5/TUBB-related microcephaly, including the core human case series, cohort context, imaging features, and experimental mechanisms. It is useful for quickly linking genotype, phenotype, neuroimaging, and pathophysiology across the foundational papers.

Key evidence excerpts (direct quotes)

From the 2023 tubulinopathy mechanism review abstract: “Recent studies, however, have highlighted the impact of tubulin mutations on microtubule-associated proteins (MAPs).” (cushion2023mappingtubulinmutations pages 1-2)
From the 2016 imaging correlates abstract: tubulin-mutation patients had “multiple cortical and subcortical abnormalities, including microcephaly, ventriculomegaly, abnormal gyral and sulcal patterns (termed ‘dysgyria’), a small or absent corpus callosum, and a small pons.” (mutch2016disordersofmicrotubule pages 1-3)

Limitations of this report

OMIM/Orphanet/MeSH/ICD-10/ICD-11 identifiers and ClinVar-specific variant assertions could not be retrieved with the currently available tools in this run; therefore, identifier mapping and ACMG/AMP classifications are not exhaustively enumerated.
Epidemiology and prognosis data specific to TUBB5-related microcephaly were not found in the retrieved evidence; conclusions are therefore largely phenotype- and mechanism-based.

References

(oegema2015recognizablecerebellardysplasia pages 3-5): Renske Oegema, Thomas D. Cushion, Ian G. Phelps, Seo-Kyung Chung, Jennifer C. Dempsey, Sarah Collins, Jonathan G.L. Mullins, Tracy Dudding, Harinder Gill, Andrew J. Green, William B. Dobyns, Gisele E. Ishak, Mark I. Rees, and Dan Doherty. Recognizable cerebellar dysplasia associated with mutations in multiple tubulin genes. Human molecular genetics, 24 18:5313-25, Sep 2015. URL: https://doi.org/10.1093/hmg/ddv250, doi:10.1093/hmg/ddv250. This article has 105 citations and is from a domain leading peer-reviewed journal.
(OpenTargets Search: microcephaly-TUBB5,TUBB): Open Targets Query (microcephaly-TUBB5,TUBB, 13 results). Buniello, A. et al. (2025). Open Targets Platform: facilitating therapeutic hypotheses building in drug discovery. Nucleic Acids Research.
(cushion2023mappingtubulinmutations pages 1-2): Thomas D. Cushion, Ines Leca, and David A. Keays. Mapping tubulin mutations. Frontiers in Cell and Developmental Biology, Feb 2023. URL: https://doi.org/10.3389/fcell.2023.1136699, doi:10.3389/fcell.2023.1136699. This article has 27 citations.
(breuss2012mutationsinthe pages 1-2): Martin Breuss, Julian Ik-Tsen Heng, Karine Poirier, Guoling Tian, Xavier Hubert Jaglin, Zhengdong Qu, Andreas Braun, Thomas Gstrein, Linh Ngo, Matilda Haas, Nadia Bahi-Buisson, Marie-Laure Moutard, Sandrine Passemard, Alain Verloes, Pierre Gressens, Yunli Xie, Kathryn J.H. Robson, Deepa Selvi Rani, Kumarasamy Thangaraj, Tim Clausen, Jamel Chelly, Nicholas Justin Cowan, and David Anthony Keays. Mutations in the β-tubulin gene tubb5 cause microcephaly with structural brain abnormalities. Cell Reports, 2:1554-1562, Dec 2012. URL: https://doi.org/10.1016/j.celrep.2012.11.017, doi:10.1016/j.celrep.2012.11.017. This article has 224 citations and is from a highest quality peer-reviewed journal.
(breuss2012mutationsinthe pages 5-6): Martin Breuss, Julian Ik-Tsen Heng, Karine Poirier, Guoling Tian, Xavier Hubert Jaglin, Zhengdong Qu, Andreas Braun, Thomas Gstrein, Linh Ngo, Matilda Haas, Nadia Bahi-Buisson, Marie-Laure Moutard, Sandrine Passemard, Alain Verloes, Pierre Gressens, Yunli Xie, Kathryn J.H. Robson, Deepa Selvi Rani, Kumarasamy Thangaraj, Tim Clausen, Jamel Chelly, Nicholas Justin Cowan, and David Anthony Keays. Mutations in the β-tubulin gene tubb5 cause microcephaly with structural brain abnormalities. Cell Reports, 2:1554-1562, Dec 2012. URL: https://doi.org/10.1016/j.celrep.2012.11.017, doi:10.1016/j.celrep.2012.11.017. This article has 224 citations and is from a highest quality peer-reviewed journal.
(breuss2012mutationsinthe pages 7-9): Martin Breuss, Julian Ik-Tsen Heng, Karine Poirier, Guoling Tian, Xavier Hubert Jaglin, Zhengdong Qu, Andreas Braun, Thomas Gstrein, Linh Ngo, Matilda Haas, Nadia Bahi-Buisson, Marie-Laure Moutard, Sandrine Passemard, Alain Verloes, Pierre Gressens, Yunli Xie, Kathryn J.H. Robson, Deepa Selvi Rani, Kumarasamy Thangaraj, Tim Clausen, Jamel Chelly, Nicholas Justin Cowan, and David Anthony Keays. Mutations in the β-tubulin gene tubb5 cause microcephaly with structural brain abnormalities. Cell Reports, 2:1554-1562, Dec 2012. URL: https://doi.org/10.1016/j.celrep.2012.11.017, doi:10.1016/j.celrep.2012.11.017. This article has 224 citations and is from a highest quality peer-reviewed journal.
(bahibuisson2014thewidespectrum pages 3-4): Nadia Bahi-Buisson, Karine Poirier, Franck Fourniol, Yoann Saillour, Stéphanie Valence, Nicolas Lebrun, Marie Hully, Catherine Fallet Bianco, Nathalie Boddaert, Caroline Elie, Karine Lascelles, Isabelle Souville, Cherif Beldjord, and Jamel Chelly. The wide spectrum of tubulinopathies: what are the key features for the diagnosis? Brain : a journal of neurology, 137 Pt 6:1676-700, Jun 2014. URL: https://doi.org/10.1093/brain/awu082, doi:10.1093/brain/awu082. This article has 361 citations.
(mutch2016disordersofmicrotubule pages 1-3): C. Mutch, A. Poduri, M. Sahin, B. Barry, Christopher A. Walsh, and A. Barkovich. Disorders of microtubule function in neurons: imaging correlates. American Journal of Neuroradiology, 37:528-535, Mar 2016. URL: https://doi.org/10.3174/ajnr.a4552, doi:10.3174/ajnr.a4552. This article has 93 citations and is from a peer-reviewed journal.
(breuss2012mutationsinthe pages 4-5): Martin Breuss, Julian Ik-Tsen Heng, Karine Poirier, Guoling Tian, Xavier Hubert Jaglin, Zhengdong Qu, Andreas Braun, Thomas Gstrein, Linh Ngo, Matilda Haas, Nadia Bahi-Buisson, Marie-Laure Moutard, Sandrine Passemard, Alain Verloes, Pierre Gressens, Yunli Xie, Kathryn J.H. Robson, Deepa Selvi Rani, Kumarasamy Thangaraj, Tim Clausen, Jamel Chelly, Nicholas Justin Cowan, and David Anthony Keays. Mutations in the β-tubulin gene tubb5 cause microcephaly with structural brain abnormalities. Cell Reports, 2:1554-1562, Dec 2012. URL: https://doi.org/10.1016/j.celrep.2012.11.017, doi:10.1016/j.celrep.2012.11.017. This article has 224 citations and is from a highest quality peer-reviewed journal.
(breuss2016mutationsinthe pages 1-2): Martin Breuss, Tanja Fritz, Thomas Gstrein, Kelvin Chan, Lyubov Ushakova, Nuo Yu, Frederick W. Vonberg, Barbara Werner, Ulrich Elling, and David A. Keays. Mutations in the murine homologue of tubb5 cause microcephaly by perturbing cell cycle progression and inducing p53-associated apoptosis. Journal of Cell Science, 129:e1.1-e1.1, Apr 2016. URL: https://doi.org/10.1242/jcs.190165, doi:10.1242/jcs.190165. This article has 48 citations and is from a domain leading peer-reviewed journal.
(sferra2023editorialtubulinopathiesfundamental pages 1-3): Antonella Sferra, Enrico Bertini, and Georg Haase. Editorial: tubulinopathies: fundamental and clinical challenges. Frontiers in Cellular Neuroscience, Oct 2023. URL: https://doi.org/10.3389/fncel.2023.1296958, doi:10.3389/fncel.2023.1296958. This article has 4 citations.
(breuss2012mutationsinthe media bf68cff9): Martin Breuss, Julian Ik-Tsen Heng, Karine Poirier, Guoling Tian, Xavier Hubert Jaglin, Zhengdong Qu, Andreas Braun, Thomas Gstrein, Linh Ngo, Matilda Haas, Nadia Bahi-Buisson, Marie-Laure Moutard, Sandrine Passemard, Alain Verloes, Pierre Gressens, Yunli Xie, Kathryn J.H. Robson, Deepa Selvi Rani, Kumarasamy Thangaraj, Tim Clausen, Jamel Chelly, Nicholas Justin Cowan, and David Anthony Keays. Mutations in the β-tubulin gene tubb5 cause microcephaly with structural brain abnormalities. Cell Reports, 2:1554-1562, Dec 2012. URL: https://doi.org/10.1016/j.celrep.2012.11.017, doi:10.1016/j.celrep.2012.11.017. This article has 224 citations and is from a highest quality peer-reviewed journal.
(breuss2012mutationsinthe media efecc53f): Martin Breuss, Julian Ik-Tsen Heng, Karine Poirier, Guoling Tian, Xavier Hubert Jaglin, Zhengdong Qu, Andreas Braun, Thomas Gstrein, Linh Ngo, Matilda Haas, Nadia Bahi-Buisson, Marie-Laure Moutard, Sandrine Passemard, Alain Verloes, Pierre Gressens, Yunli Xie, Kathryn J.H. Robson, Deepa Selvi Rani, Kumarasamy Thangaraj, Tim Clausen, Jamel Chelly, Nicholas Justin Cowan, and David Anthony Keays. Mutations in the β-tubulin gene tubb5 cause microcephaly with structural brain abnormalities. Cell Reports, 2:1554-1562, Dec 2012. URL: https://doi.org/10.1016/j.celrep.2012.11.017, doi:10.1016/j.celrep.2012.11.017. This article has 224 citations and is from a highest quality peer-reviewed journal.
(breuss2012mutationsinthe pages 6-7): Martin Breuss, Julian Ik-Tsen Heng, Karine Poirier, Guoling Tian, Xavier Hubert Jaglin, Zhengdong Qu, Andreas Braun, Thomas Gstrein, Linh Ngo, Matilda Haas, Nadia Bahi-Buisson, Marie-Laure Moutard, Sandrine Passemard, Alain Verloes, Pierre Gressens, Yunli Xie, Kathryn J.H. Robson, Deepa Selvi Rani, Kumarasamy Thangaraj, Tim Clausen, Jamel Chelly, Nicholas Justin Cowan, and David Anthony Keays. Mutations in the β-tubulin gene tubb5 cause microcephaly with structural brain abnormalities. Cell Reports, 2:1554-1562, Dec 2012. URL: https://doi.org/10.1016/j.celrep.2012.11.017, doi:10.1016/j.celrep.2012.11.017. This article has 224 citations and is from a highest quality peer-reviewed journal.
(oegema2015recognizablecerebellardysplasia pages 14-15): Renske Oegema, Thomas D. Cushion, Ian G. Phelps, Seo-Kyung Chung, Jennifer C. Dempsey, Sarah Collins, Jonathan G.L. Mullins, Tracy Dudding, Harinder Gill, Andrew J. Green, William B. Dobyns, Gisele E. Ishak, Mark I. Rees, and Dan Doherty. Recognizable cerebellar dysplasia associated with mutations in multiple tubulin genes. Human molecular genetics, 24 18:5313-25, Sep 2015. URL: https://doi.org/10.1093/hmg/ddv250, doi:10.1093/hmg/ddv250. This article has 105 citations and is from a domain leading peer-reviewed journal.
(bahibuisson2014thewidespectrum pages 3-3): Nadia Bahi-Buisson, Karine Poirier, Franck Fourniol, Yoann Saillour, Stéphanie Valence, Nicolas Lebrun, Marie Hully, Catherine Fallet Bianco, Nathalie Boddaert, Caroline Elie, Karine Lascelles, Isabelle Souville, Cherif Beldjord, and Jamel Chelly. The wide spectrum of tubulinopathies: what are the key features for the diagnosis? Brain : a journal of neurology, 137 Pt 6:1676-700, Jun 2014. URL: https://doi.org/10.1093/brain/awu082, doi:10.1093/brain/awu082. This article has 361 citations.

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Pathophysiology

Pathograph

Phenotypes

Genetic Associations

Medical Actions

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References & Deep Research

References

Deep Research

Disease Characteristics Research Template

Target Disease

Research Objectives

1. Disease Information

2. Etiology

3. Phenotypes

4. Genetic/Molecular Information

5. Environmental Information

6. Mechanism / Pathophysiology

7. Anatomical Structures Affected

8. Temporal Development

9. Inheritance and Population

10. Diagnostics

11. Outcome/Prognosis

12. Treatment

13. Prevention

14. Other Species / Natural Disease

15. Model Organisms

Citation Requirements

Output Format

Comprehensive Disease Characteristics Research Report: TUBB/TUBB5-related Microcephaly (Tubulinopathy)

Target disease

1. Disease information

1.1 Concise overview

1.2 Key identifiers (resource gaps)

1.3 Synonyms / alternative names

1.4 Evidence provenance

2. Etiology

2.1 Disease causal factors

2.2 Risk factors

2.3 Protective factors

2.4 Gene–environment interactions

3. Phenotypes

3.1 Core phenotype spectrum (human)

3.2 Phenotype frequencies and quantitative data

3.3 Suggested HPO terms

3.4 Quality of life impact

4. Genetic / molecular information

4.1 Causal genes

4.2 Pathogenic variants (reported)

4.3 Inheritance pattern

4.4 Modifier genes / epigenetics

5. Environmental information

6. Mechanism / pathophysiology

6.1 Current mechanistic understanding (causal chain)

6.2 Key mechanistic evidence (primary)

6.3 Broader mechanistic framing from authoritative reviews (recent)

6.4 Suggested ontology terms

7. Anatomical structures affected

7.1 Organ/system level

7.2 Suggested UBERON terms (examples)

8. Temporal development

8.1 Onset

8.2 Progression

9. Inheritance and population

9.1 Epidemiology

9.2 Inheritance

9.3 Population demographics

10. Diagnostics

10.1 Clinical/imaging diagnosis

10.2 Genetic testing approach (real-world implementation)

10.3 Differential diagnosis

11. Outcome / prognosis

12. Treatment

12.1 Disease-modifying therapy

12.2 Supportive / symptomatic management (real-world)

12.3 Clinical trials