| Gene (HGNC symbol) | Key paper (year) | PMID | 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 | (pqac-00000001, pqac-00000004, pqac-00000011) |
| **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 | (pqac-00000015) |
| **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 | (pqac-00000002, pqac-00000019) |
| **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 | (pqac-00000003) |


*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.*