Figure 3. Mutation carriers identified in the subject family with congenital nystagmus. The DNA sequence containing the identified duplication
region was amplified by a new pair of primers. Two different allele fragments, a 299 bp PCR fragment that indicated the mutant
allele containing the 19 bp duplication and a 280 bp fragment that represented the wild-type allele, would be detected in
the female carriers. We can see that all normal individuals obtained only the wild-type alleles of 280 bp, and all male patients
only obtained the mutant alleles of 299 bp, which was consistent with the sequence analysis results. All heterozygous individuals
(II:1, III:3, III:5, III:7, III:13, and III:14) were determined to be mutation carriers. N: Normal individual; ND: Normal
male or female in this family. These individuals (labeled by ND) cannot be identified on the pedigree due to our carelessness
and incomplete records of family information during the sample collection, and now we are no longer in touch with them.