Objective：To describe inherited bilateral ectopia lentis caused by p.Arg974CYs mutation in the FBN1 gene. Methods：The boy’s clinical data and family history were recorded. Ophthalmic examination and family gene detection were performed for the boy. Detailed ophthalmic examination included vision，lens position by slit-lamp examination，optometry，central corneal thickness，corneal curvature，fundus examination，axial length，ophthalmic ultrasound，and intraocular pressure measurement. Agilent exon array micro－processor capture and high-throughput sequencing were used for gene detection. Results：A heterozygous mutation，C2920C>T（p.Arg974Cys），of the FBN1 gene was found in the affected mother and the son，while it was not found in the father who was unaffected. The study on the clinical manifestation of this disease revealed several new clinical manifestations，including normal corneal curvature accompanied by amblyopia. Conclusion：Isolated ectopia lentis is closely associated with Marfan syndrome. Potential aortic dissection or aortic aneurysm caused by FBN1 mutation may turn isolated ectopia lentis into Marfan syndrome. Intraocular lens implantation is recommended for such patients after they become adults.
