[Genetic variant analysis of a pedigree affected with lymphedema-distichiasis syndrome]

To analyze FOXC2 gene variant in a family affected with lymphodema-distichiasis syndrome (LDS).

Peripheral blood samples were collected for the extraction of DNA and protein. Whole-exome sequencing was carried out to detect variants in the proband. Suspected variant was validated by Sanger sequencing. Western blotting was used to detect changes in protein expression.

The proband and his mother were both found to carry a heterozygous nonsense variant c.177C>G (p.Tyr59X) of the FOXC2 gene, which was previously unreported. Down-regulated expression of FOXC2 was detected by Western blotting. Prenatal ultrasonography of the fetus indicated increased nuchal thickness. Amniocentesis was performed at 21+1 weeks of pregnancy, genetic testing suggested that the fetus also carried the c.177C>G variant.

The patients' condition may be attributed to the heterozygous nonsense variant c.177C>G of the FOXC2 gene, which resulted in a significant decrease in FOXC2 expression. Increased nuchal thickness may also be related with decreased FOXC2 expression. Above finding has expanded the variant spectrum of the FOXC2 gene.