Research results utilizing the research resources of BioBank Japan (BBJ) have been published in Annals of the Rheumatic Diseases.

An international research team led by Chikashi Terao, a team leader at RIKEN, has conducted the largest study in Japan on the association between mosaic chromosomal alterations (mCAs) and rheumatoid arthritis (RA). The study analyzed DNA samples from approximately 180,000 individuals registered in BioBank Japan and around 2,400 RA patients from the IORRA (Institute of Rheumatology, RA) cohort. The findings revealed that mosaic loss of the Y chromosome (mLOY), a phenomenon affecting male sex chromosomes, is a risk factor for late-onset RA (LORA). In contrast, an increase of mLOY was associated with a lower risk of young-onset RA. Moreover, in LORA, mLOY interacts with the polygenic risk score (PRS), further increasing the risk of disease development.

Original paper

Mosaic loss of chromosome Y characterises late-onset rheumatoid arthritis and contrasting associations of polygenic risk score based on age at onset
Ann Rheum Dis. 2025 Feb 19:S0003-4967(25)00184-0