Host: The Japanese Society of Toxicology
Name : The 50th Annual Meeting of the Japanese Society of Toxicology
Date : June 19, 2023 - June 21, 2023
Recent advances in cytogenetic technologies have enabled to detection of various chromosomal alterations. In particular, sex chromosomes often develop numerical or structural changes. For example, the Y chromosome contains a region enriched by repetitive sequences (“the AZF region”). This region is a hotspot for microdeletions and duplications, and more than 30% of Japanese men have microdeletions in this region. Copy-number variants in this region are known as risk factors for azoospermia, although the Japanese-specific microdeletion does not affect spermatogenesis.
Of note, recent studies have shown that Y chromosomes are often lost in the somatic cells of elderly people. In these men, 45,X cells gradually accumulate in the body. Reportedly, 45,X cells are present in about 40% of men aged 70 years. Age-related Y chromosome loss is known as a risk factor for early death, cancer, and Alzheimer's disease. We found that somatic Y-chromosomal loss is not limited to elderly men, but also occurs at any time of life. Mosaic Y chromosomal loss in children and young men is a risk for disorders of sex development, growth retardation, and infertility. The frequency of Y chromosomal loss is significantly higher in smokers than in non-smokers, indicating that environmental factors play an important role in this phenomenon. On the other hand, we have found that the Japanese-specific AZF deletion does not increase the risk of Y chromosomal loss.
In my talk, I would like to introduce new findings on sex chromosomal variations and discuss possible roles of environmental factors in the development of such chromosomal changes.
