To detect and analyze GUCY2D gene mutations in a family with Leber Congenital Amaurosis (LCA) in China. Researchers collected peripheral blood samples from affected family members in three generations. Genomic DNA was extracted and all 20 exons of the GUCY2D gene were amplified using the DNA of the proband as the template. The ABI 3100 automated sequencer was used for sequencing. The sequencing results revealed one Single Nucleotide Polymorphism (SNP): c.154G.T (p.A52S) on exon 2 of the GUCY2D gene. The encoded amino acid changed from alanine to serine. All affected family members carried this SNP.