Initially, two separate clusters of TUBB3 pathogenic variants had been proposed to specifically be associated with CDCBM (e.g., p.Arg46Gly, p.Gly82Arg, p.Thr178Met, p.Glu205Lys, p.Glu288Lys, p.Ala302Val, p.Met323Val, p.Pro357Leu, p.Met388Val) or CFEOM (e.g., p.Arg262Cys, p.Arg262His, p.Arg380Cys, p.Glu410Lys, p.Asp417Asn, and p.Asp417His) [54]. This evidence concerns the gene TUBB3 and congenital fibrosis of the extraocular muscles.