Free previewYou're reading the free part of this topic. The rest is included with Clinical.See what's included
Congenital cranial dysinnervation disorders (CCDD)
Strabismus
Key Points
- •CCDDs are genetically determined cranial nerve developmental disorders - the common thread is aberrant innervation, absent cranial nerves, or failed axonal guidance, NOT primary muscular disease; MRI shows absent/hypoplastic cranial nerves
- •Duane syndrome (most common CCDD): absent CN VI → aberrant CN III innervation of LR → co-contraction on adduction → globe retraction + fissure narrowing; genes: SALL4 (Okihiro), CHN1
- •CFEOM gene-phenotype correlations: CFEOM1 = KIF21A (AD, ptosis + restricted upgaze); CFEOM2 = PHOX2A/ARIX (AR, total ophthalmoplegia); CFEOM3 = TUBB3 (AD, variable, intellectual disability possible)
- •HGPPS: ROBO3 mutations prevent axonal midline crossing → complete absence of horizontal gaze + progressive scoliosis; MRI shows butterfly-shaped medulla; convergence preserved
- •Moebius syndrome: bilateral CN VI + CN VII agenesis (congenital facial diplegia + convergent squint); associated with limb anomalies (Poland sequence) and first-trimester misoprostol exposure
Free preview ends here
Keep reading Congenital cranial dysinnervation disorders (CCDD)
12 more sections are included with the Clinical plan.
- Definition
- Epidemiology
- Aetiology and causes
- Pathogenesis
- Classification
- Clinical features