A first molecular approach towards CGG repeat expansion in FMR1 gene in systemic lupus erythematosus and in Sjögren's syndrome: a preliminary report.

Co-occurrent autoimmune disease and fragile X syndrome has been reported in the literature and we have therefore studied the expansion of Cytosine-Guanine-Guanine (CGG) repeat in FMR1 gene in a series of females with autoimmune diseases such as systemic lupus erythematosus and Sjögren's syndrome, with PCR and Southern blot methods. The average length of trinucleotide repeat was not increased in these female patients as compared with controls. These preliminary data on a short series of patients suggest a possible absence of trinucleotide repeat expansion abnormality associated with autoimmune diseases such as systemic lupus erythematosus and Sjögren's syndrome.