[A linkage study of cytotoxic T lymphocyte-associated antigen 4 gene and Graves' disease in northern Chinese Han ethnic].

Objective: To determine if the cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) gene, which is located on chromosome 2q31-q33, is the major susceptibility gene for Graves' disease (GD) of northern Chinese Han nationality.

Methods: Five highly polymorphic microsatellite markers spanning the entire region of chromosome 2q31-q33 were employed to screen 54 families with multiple incidences of GD (322 individuals) of northern Chinese Han nationality. Tow-point and multi-point Lod scores were calculated under different levels of penetrance, assuming both dominant and recessive models. Multipoint nonparametric linkage (NPL) scores were also calculated.

Results: Two-point Lod scores (theta = 0) and multipoint Lod scores of less than -2 were observed for all the markers tested, at all levels of penetrance, in both the dominant and recessive models of inheritance. P values of greater than 0.05 were observed for all the multipoint NPL scores obtained.

Conclusion: We obtained evidence against the linkage of GD with chromosome 2q31-q33, thus we are of the opinion that CTLA-4 gene is not the major susceptibility locus for Graves' disease of northern Chinese Han nationality.