[Lupus nephropathy in childhood and familial lupus. Genetic study of a family].

We report a case of a 14 1/2-year-old boy who was diagnosed of systemic lupus erythematosus in the background of an acute nephritic syndrome, 3 1/2 years after being diagnosed of idiopathic thrombocytopenic purpura. The familial history suggested the presence of other cases of SLE, which were proven with relevant clinical and laboratory studies. A genetic study for disease markers was carried out and a correlation was found with haplotypes HLA A25, B18, BW6, DRX, and DQW; C2 deficiency was ruled out. We conclude that it is of paramount importance to rule out the existence of familial SLE in front of infantile SLE, particularly in boys, and we emphasize the necessity of keeping on further searching for genetic markers of the disease.