Genes that escape from X-chromosome inactivation and sexual dimorphism of systemic lupus erythematosus.

X chromosome inactivation can balance the effects of the two X chromosomes in females, and emerging evidence indicates that numerous genes on the inactivated X chromosome have the potential to evade inactivation. The mechanisms of escape include modification of DNA, RNA, histone, epitope, and various regulatory proteins, as well as the spatial structure of chromatin. The study of X chromosome inactivation escape has paved the way for investigating sex dimorphism in human diseases, particularly autoimmune diseases. It has been demonstrated that the presence of TLR7, CD40L, IRAK-1, CXCR3, and CXorf21 significantly contributes to the prevalence of SLE (systemic lupus erythematosus) in females. This article mainly reviews the molecular mechanisms underlying these genes that escape from X-chromosome inactivation and sexual dimorphism of systemic lupus erythematosus. Therefore, elucidating the molecular mechanisms underlying sexual dimorphism in SLE is not only crucial for diagnosing and treating the disease, but also holds theoretical significance in comprehensively understanding the development and regulatory mechanisms of the human immune system.

Digit ratio (2D:4D) in Chinese women with gastric cancer.

OBJECTIVES: Digit ratio, especially the second-to-fourth digit ratio (2D:4D), is a proxy indicator for prenatal exposure and sensitivity to sexual hormones which may influence the susceptibility to certain cancers. The aim of the present study was to investigate whether there is a possible association between 2D:4D and gastric cancer (GCA) in north Chinese women. METHODS: Photographs of the left and right hands of 167 women (controls: 113; patients: 54) were collected. Left hand, right hand, and right minus left hand (Dr-l) 2D:4D were analyzed and compared. RESULTS: The GCA group presented significantly lower 2D:4D than controls (left: P < .01; right: P < .05). No significant difference was observed in Dr-l between the two groups. In patients, there were no correlations between 2D:4D and age at GCA or tumor staging. CONCLUSIONS: Decreased 2D:4D (especially of the left hand) may suggest a higher prenatal testosterone (lower prenatal estrogen) exposure in north Chinese women with GCA.