Analysis of gene variant in a Chinese pedigree with preaxial polydactyly

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.