ObjectiveTo observe and analyze the clinical and genotypic characteristics of patients with X-linked ocular albinism type 1 (OA1) and their female carriers. MethodsA retrospective clinical study. Five unrelated families (all male) with OA1 diagnosed through genetic testing and treated at Eye & ENT Hospital of Fudan University from January 2021 to November 2025 were included. A total of 5 probands and 3 female carriers were involved. Information on the medical history and family history of all participants was collected. Four probands and 3 female carriers underwent best corrected visual acuity (BCVA), slit lamp microscopy, fundus autofluorescence, fundus color photography, and optical coherence tomography examinations. Peripheral venous blood was collected from all participants, and whole genome DNA was extracted for whole-exome sequencing to identify potential pathogenic loci, followed by pathogenicity analysis and Sanger sequencing verification. According to the relevant guidelines of the American College of Medical Genetics and Genomics (ACMG), the pathogenicity of the newly discovered genetic variations was evaluated. ResultsAll five probands were male, and their ages at the time of consultation ranged from 3 months to 18 years. All probands presented with bilateral nystagmus, with BCVA ranging from 0.1 to 0.3. Ocular examination revealed mild iris pigment distribution abnormalities in 2 cases, varying degrees of choroidal vascular exposure and mild to moderate retinal pigment loss in 3 cases; foveal hypoplasia in 3 cases, with grades ranging from Ⅲ to Ⅳ. Typical "muddy-splashed" fundus pattern could be observed from the mid-periphery to the periphery of the retina in the fundus of 3 female carriers. A total of 5 GPR143 gene variations highly correlated with the phenotype were identified through genetic testing, including 3 deletion variations (exon 1-9, exon 1, exon 2-3 deletion) and 2 nonsense variations (c.278T>A, c.333G>A). Among them, the proband in family 1 carried a hemizygous nonsense variation of GPR143 gene exon 2 c.278T>A (p.Leu93*). According to the ACMG guidelines, this variation meets the extremely strong evidence of pathogenicity (PVS1), and has not been reported in the gnomAD database, representing a novel variant with no previous literature reports (PM2_Supporting). The overall assessment was that it was a likely pathogenic variant. ConclusionsThe clinical phenotype of OA1 shows a high degree of heterogeneity. Nystagmus, foveal hypoplasia, and the characteristic "mud-splattered" fundus pattern in female carriers are important clinical diagnostic clues, but genetic testing remains the gold standard for diagnosing this disease.