ACTA2 and Mydriasis: Congenital mydriasis, which is common in MSMDS, is due to the reduced contractility of iris sphincter and dilator muscles, resulting in fixed dilated pupils.[4] The absence of iris crypts and furrows, which can be seen in congenital microcoria, may be the result of the dilator muscle hypoplasia.[12] In summary, we observed congenital mydriasis, persistent anterior TVL and early-onset retinal arteriolar tortuosity in the eyes of a 6-week-old girl with a de novo heterozygous ACTA2 gene missense mutation p.R179H causing MSMDS.