Mutations in the RYR1 gene have been associated with atypical MBS or congenital fibrosis of the extraocular muscles (CFEOM), and the mutation c.1228G>A (p.Glu410Lys) in the TUBB3 gene has been detected in a patient affected by congenital external ophthalmoplegia sparing abduction, facial weakness, anosmia, and hypogonadotropic hypogonadism, which overlaps with atypical MBS [16,17]. Here, RYR1 is linked to Mobius syndrome.