| Subtype / OMIM status | Principal gene | Inheritance | Hallmark ocular phenotype | Associated / systemic findings | Principal developmental mechanism |
|---|---|---|---|---|---|
| CFEOM1 / OMIM not asserted here | **KIF21A** | Autosomal dominant; often familial, can be de novo | Congenital bilateral ptosis; eyes typically fixed infraducted; severe limitation of upgaze with variable horizontal restriction | Usually isolated ocular phenotype, though syndromic presentations are reported in some variant contexts; MRI/human pathology show hypoplastic superior rectus and levator with oculomotor nerve abnormalities (pqac-00000001, pqac-00000004) | Gain-of-function/missense mechanism that reduces KIF21A autoinhibition, alters kinesin-microtubule behavior, and stalls superior-division CN III axon growth/guidance during development (pqac-00000001, pqac-00000002) |
| CFEOM2 / OMIM not asserted here | **PHOX2A** | Autosomal recessive | Congenital bilateral ptosis with exotropia at rest and profound restriction of ocular movements | MRI evidence of absent oculomotor and trochlear nerves; may be accompanied by pupil abnormalities in classic descriptions; generally a cranial motor neuron specification disorder (pqac-00000000) | Loss of PHOX2A function disrupts specification/development of oculomotor and trochlear motor neuron nuclei, causing failure of normal innervation to extraocular muscles (pqac-00000000) |
| CFEOM3 / OMIM not asserted here | **TUBB3** | Autosomal dominant; variable expressivity, including de novo cases | Variable congenital ophthalmoplegia, often asymmetric; ptosis may be unilateral or bilateral; limited upgaze common, horizontal deficits variable | Can be isolated or syndromic; reported associations include additional cranial/peripheral neuropathy features and white-matter/brain abnormalities depending on variant (pqac-00000000, pqac-00000007) | Missense variants in neuronal β-tubulin III alter microtubule dynamics and kinesin interaction, impairing cranial axon growth, maintenance, and guidance (pqac-00000000, pqac-00000002) |
| Rare CFEOM-associated phenotype / OMIM not asserted here | **TUBA1A** | Typically autosomal dominant / de novo in reported cases | CFEOM phenotype with congenital ophthalmoplegia/ptosis | May occur with or without malformations of cortical development; broader tubulinopathy features can be present (pqac-00000007) | Altered α-tubulin function perturbs neuronal microtubules, cranial axon guidance, and in some cases cortical development (pqac-00000007) |
| Rare CFEOM-associated phenotype / OMIM not asserted here | **TUBB2B** | Typically autosomal dominant in reported families | CFEOM/ophthalmoplegia phenotype | Can be associated with polymicrogyria and broader axon dysinnervation syndrome rather than isolated CFEOM (pqac-00000007) | Altered β-tubulin/kinesin-binding interface disrupts axon guidance and brain development (pqac-00000007) |


*Table: This table summarizes the main genetically defined CFEOM subtypes and rarer tubulin-associated presentations, highlighting inheritance, distinguishing ocular findings, systemic associations, and developmental mechanisms. It is useful as a compact knowledge-base scaffold when exact identifiers are uncertain or subtype boundaries overlap.*