BACKGROUND: The present study aimed to evaluate the pathogenicity of 5 GDF3 gene variations using functional and in silico assessment approaches in a Chinese congenital scoliosis population.

MATERIAL AND METHODS: We selected 13 patients carrying 5 variants from a congenital scoliosis cohort. The PCR products of samples were verified by Sanger sequencing. The data and sequence alignment were analyzed using Chromas and ClustalW. SIFT and PolyPhen-2 were used to predict the functional effects of each missense and amino acid substitutions. SWISS-MODEL server and Swiss-PdbViewer were used to analyze conformational changes of GDF3 structure. DUET, UCSF Chimera, and Ligplot software were used to further explore the protein stability, side chains, and hydrophobic interaction changes, respectively. Luciferase reporter gene and Western blot assays were used to perform functional assessments for every variant from the molecular level.

RESULTS: Of the 13 patients, the S212L variant reoccurred in 9 patients. The rest of the patients carried 1 missense mutation each. The variants of R84L and R84C were predicted as probably damaging loci. S212L, N215S, A251T were predicted as benign loci. In functional assays, R84L, S212L, and A251T display inhibitory effects on functional assays. N251S mutation showed a negative effect in protein expression assays but not in luciferase reporter gene assays. The variant of R84C displayed no negative effects on 2 functional assays.

CONCLUSIONS: Our results suggest that the 4 of the 5 variants in GDF3 gene contribute different pathogenicity in congenital scoliosis, which may provide molecular evidence for clinical genetic testing.

Keywords: Computer Simulation, genetic variation, Growth Differentiation Factor 3, Molecular Biology, Scoliosis, Transforming Growth Factor beta