Sometimes referred to as Bloom-Torre-Machacek syndrome, Bloom syndrome predominantly affects those with a Eastern or Central European background; Ashkenazi Jews in particular. It is estimated that the disorder impacts approximately one out of every 48,000 individuals with this heritage. Its incidence within other races is not yet fully understood.
Bloom syndrome is characterised by a condition known as genomic instability. To put this another way, mutations within a specific gene known as BLM will cause changes in the formation of some proteins associated with DNA replication (1). This is the primary reason why genetic instability is the most predominant trait.
The rapid changes within genetic structures lead to some common symptoms which are exhibited by nearly all patients. A noticeably short stature and a rash on the face that worsens when the individual is exposed to the sun are the most common observations. Other symptoms can include:
This disease is found within the larger category of autosomal recessive disorders. This signifies that both parents can carry the mutated BLM gene and yet, neither may exhibit any of the symptoms associated with Bloom syndrome. It can therefore be difficult to track those at risk. Some theorise that this is also the reason why it was not until 1954 that the disease was given official recognition.
Cancer is often caused by uncontrolled genetic and cellular mutations within the body. Thus, it should come as no surprise that those who have been diagnosed with Bloom syndrome are at a higher predisposition of developing some form of cancer during their lifetime. It has also been shown that the onset of many cancers occurs notably earlier when compared to the general population. Some common types that are often seen will include:
Another defining characteristic of Bloom syndrome is that it is not uncommon for multiple cancers to develop independently of one another at the same time. These are sometimes referred to as metachronous cancers.
It is first important to mention that there is currently no known form of effective treatment of the condition itself. It is thought that advances in early detection and genetic manipulation may provide some hope for future generations. The main complicating factor is the increased likelihood of developing some form of cancer (particularly if multiple cancers are present simultaneously). Further risks include mental retardation, poor lung function and diabetes. All of these will have a profound impact upon the overall life expectancy rates.
The average life expectancy of an infant born with Bloom syndrome is 27 years (2). This once again depends upon the occurrence of cancer and the type detected. The prognosis associated with those who have multiple forms will obviously be worse when compared to a patient with a relatively treatable variant such as an isolated carcinoma.
However, certain treatment options may be able to prolong the life of the patient. This is also assuming that there are no other debilitating underlying conditions present. For example, an individual with diabetes who has recently been diagnosed with cancer may have fewer pharmacological treatment options. This could dramatically impact the overall life expectancy.
It can be assumed that further advancements in the field of cancer research will provide additional treatment options that may be able to increase life expectancy rates. Innovations in genetic engineering techniques could likewise open up unique possibilities that are not yet known to clinicians. One confounding factor is the rather low incidence rate along with the specific population that Bloom syndrome tends to target. It will therefore be quite interesting to see any advancements that may occur within the next few decades.