A novel mutation in LMX1B gene causes nail-patella syndrome in a large Chinese family.

We conducted clinical and genetic studies in a large Chinese family with nail-patella syndrome (NPS) involving multi-organ (such as limb, renal and eye) and investigated the functional consequences of a novel LMX1B mutation identified in the family. Twenty individuals at risk for inheriting NPS in the Chinese family participated in the study and a physical examination was performed and blood was drawn for DNA extraction. Linkage analysis and mutation screening of LMX1B gene were performed and the functional study in vitro for the mutation was conducted by luciferase assay. The disease phenotype of this family was linked to D9S290 with LOD Score=5.8 at theta=0; a novel mutation 742 A>G (R248G) within the homeodomain was found in a conserved site and co-segregated with the disease phenotype of the family. The functional study in vitro by luciferase assay indicated that the R248G mutation within the binding domain of the gene affected the transactivation. This is the first report that a mutation in the LMX1B gene causes NPS in a Chinese population, which will expand the spectrum of mutations in the LMX1B gene and provide insight into the underlining pathology of NPS.