Which are the causes of Monosomy 6p25?

Monosomy 6p25 is a rare chromosomal disorder characterized by the deletion of a portion of the short arm of chromosome 6. This condition is caused by the loss of genetic material in the 6p25 region, specifically the deletion of one copy of the genetic material from this region. Monosomy 6p25 can occur sporadically or be inherited from a parent who carries a balanced translocation involving chromosome 6.

There are several causes of Monosomy 6p25:

1. De novo deletions: In many cases, Monosomy 6p25 occurs as a random event during the formation of reproductive cells or early embryonic development. These de novo deletions are not inherited from either parent and are typically not seen in other family members.

2. Balanced translocations: In some instances, one of the parents may carry a balanced translocation involving chromosome 6. A balanced translocation occurs when a piece of one chromosome breaks off and attaches to another chromosome, without any loss or gain of genetic material. However, when a parent with a balanced translocation passes on the translocated chromosome to their child, it can result in an unbalanced translocation in the child, leading to Monosomy 6p25.

3. Chromosomal rearrangements: Rarely, Monosomy 6p25 can also occur due to other chromosomal rearrangements, such as inversions or duplications, which disrupt the normal structure of chromosome 6 and result in the loss of genetic material in the 6p25 region.

It is important to note that the exact cause of Monosomy 6p25 may vary from individual to individual, and in many cases, the specific cause remains unknown. Genetic counseling and testing can help determine the underlying cause of Monosomy 6p25 in an affected individual and provide valuable information for families regarding the risk of recurrence and available treatment options.