For the first time, children developing systemic lupus erythematosus (SLE) under the age of 16 have been found to have significantly different polymorphisms of the Pvull and Xbal genes for oestrogen receptor α (ORα) compared to those developing the disease over the age of 16.

In a case-control study carried out in Korea of 137 female patients with SLE and 268 matched controls, 41 cases developed the disease under the age of 16.

Genomic DNA was extracted from the peripheral blood of all participants, and Pvull and Xbal restriction fragment length polymorphisms of ORα investigated using polymerase chain reaction primers.

PP, Pp and xx genotypes occurred significantly less frequently in cases developing SLE in childhood than in controls (p = 0.005, 0.05, and 0.026 respectively). The PP genotype also occurred significantly less frequently in childhood onset than adult onset SLE (p = 0.016). Additionally patients with the Xx genotype had earlier onset of SLE than those with xx genotype (p = 0.025). The frequency of the combined ppXx genotype was significantly greater in childhood onset SLE than in controls (p = 0.0009) or adult onset SLE (p = 0.027).

PvuII and Xbal polymorphisms of ORα have already been investigated in other diseases, but this is the first time it has been studied in childhood onset SLE. The authors conclude that this indirectly supports the concept that oestrogen is involved in the pathogenesis of SLE. However the study was limited by the small number of cases of childhood onset SLE. Larger studies in different populations are now needed.