Sex chromosomes contribute to the majority of chromosome loss events with increasing age. In females, the X chromosome can account for up to 72% of the observed micronuclei of which 37% appear to be lacking a functional kinetochore assembly possibly due to X chromosome inactivation. Multiple studies have shown that the frequencies of autosome-positive micronuclei in both genders and of sex chromosome-positive MN in men were similar and remained unchanged in older groups while the frequency of X-positive MN in women was higher than the average frequency of autosome-positive MN and continued to increase until the oldest age.