Patients with sporadic Duane's retraction syndrome (congenital aberrant innervation) appear to have a significant increase in the number of associated congenital malformations. These are primarily facial anomalies, ear and hearing anomalies, skeletal deformities, and roentgenographic malformations in the upper vertebral column and rib cage. The critical time in embryologic development resulting in these anomalies is the fourth to the eighth week of gestation.
Pfaffenbach DD, Cross HE, Kearns TP. Congenital Anomalies in Duane's Retraction Syndrome. Arch Ophthalmol. 1972;88(6):635-639. doi:10.1001/archopht.1972.01000030637013