The Mobius sequence: A relook

Mobius sequence, because the term sequence defines a cascade of secondary e vents after an embryonic insult from heterogeneous causes. Classic clinical findings include evidence of sixth and seventh cranial nerve involvement, often with associated malformations of limbs, craniofacial structures, and other cranial nerves. Methods:A prospective study was undertaken in Sweden of 25 patients who showed characteristic findings of Mobius sequence. Resul ts: Of the patients who did not have strabismus surgery, 10 patients had st raight eyes in the primary position, 7 had esotropia, 2 had exotropia, and 1 had hypertropia. All had significant limitation of abduction, except 1 pa tient with exotropia who showed minimal underaction on abduction but a larg e limitation of adduction. In the description in these early cases, some pa tients manifested a clinical pattern resembling a horizontal gaze paresis. Narrowing of the palpebral fissure on adduction Similar to that seen in Dua ne syndrome was observed in a few cases. Two patients had ptosis. Nineteen patients had diminished facial expression bilaterally, often asymmetric, an d 6 cases appeared to be unilateral. Seven patients had abnormal tearing. A ssociated systemic findings included Poland anomaly (2), club feet or other limb anomalies (8), micrognathia (8), tongue malformations (17), cleft pal ate (5), and speech problems (18). An unusual finding was autism syndrome ( 6) or autism-like syndrome (1). Conclusions: The associated findings in Mob ius sequence may give further clues to the location and timing of the devel opmental disturbance. The wide range of ocular motility patterns suggests t hat the previous concept of a lesion solely in the sixth nerve nucleus is a n inadequate explanation for these findings.