BLM gene

BLM gene – Bloom syndrome

Mutations in the BLM gene cause Bloom Syndrome.  People with Bloom Syndrome tend to have short stature, have prominent facial features such as nose and ears, sensitivity to the sun, infertility, and an increased risk of cancers. While individuals with a single pathogenic BLM variant do not have Bloom syndrome, there is evidence they may have an increased risk of colon cancer.

Bloom syndrome is inherited in an autosomal recessive manner.  Therefore, to have bloom syndrome a defective copy of the BLM gene must be received from both the mother and the father.  However, those who are heterozygous for the BLM gene, meaning they have only one defected copy and are carriers for the disease, are thought to have an increased risk for colorectal cancer.  It is recommended that these individuals  should speak with their doctors about having more frequent colonoscopies.

The BLM gene is very important in making a protein that plays a crucial role in DNA replication. When there is a mutation in the BLM gene, the protein is unable to function properly.  This results in a much higher rate of mistakes in DNA replication, causing an increased amount of mutations that prevent cells from being able to function normally.   Sometimes, these abnormalities allow cells to divide in an unconstrained way, leading to cancer.

Resources

https://ghr.nlm.nih.gov/condition/bloom-syndrome#inheritance

https://www.nccn.org/professionals/physician_gls/pdf/genetics_colon.pdf