Abstract: Objective To analyze the clinical features of genotypes in a family with congenital nystagmus and determine the diseasecausing mutation. Methods Thirteen members in a family (6 patients and 7 normal subjects) in Sanya City, Hainan Province, China, who admitted to our hospital were recruited in this study in December 2013. A detailed clinical ophthalmic examination was performed for all patients. They underwent visual acuity test, anterior segment slit lamp examination, eye position fundus examination. Their clinical phenotype data were analyzed. Mutations in FRMD7 and GPE143 were determined by PCR-based DNA sequencing assays and multiplex PCR assays for deletions. Results Six patients in the family were males with the onset at the age of 0-6 months. The type of nystagmus in the family was horizontal jerk nystagmus. Only one patient had choroid coloboma. All patients had head oscillation, iris depigmentation, foveal hypoplasia and reduced visual acuity. Conclusion The c.360+5G＞ T mutation of GPR143 molecular can cause X-linked congenital idiopathic nystagmus.