HOXA1 and congenital fibrosis of the extraocular muscles: Individual CCDDs can be sporadic (e.g., most Duane retraction syndrome) [2], autosomal dominant (e.g., congenital fibrosis of the extraocular muscles type [CFEOM] type 1 or 3 [3, 4], autosomal recessive (e.g., the HOXA1 spectrum or CFEOM2 [5, 6], or chromosomal in origin [7].