Objective: To analyze the pathogenic variant of preaxial polydactyly in a Chinese Han pedigree and identify the cause of polydactyly.
Methods: The peripheral blood DNA of the proband and her parents was extracted. The polydactyly-related genes were detected by trio whole exome sequencing, and the suspected pathogenic gene was screened out. Sanger sequencing was applied to other members of the pedigree.
Results: The results of gene sequencing showed that the LMBR1 gene had a heterozygous variant of c.423+4909(IVS5)C>T in 6 patients of the pedigree. The same variant was not detected in family members with normal phenotype. Based on the ACMG guidelines, c.423+4909(IVS5)C>T of the LMBR1 gene was predicted to be pathogenic (PM1+PM2+PP1-S(PS)+PP4+PP5).
Conclusion: The heterozygous C>T variant at position 4909 of intron 5 of the LMBR1 gene probably underlies the disease in this pedigree.