The uses for DNA testing are definitely expanding. Where once we equated DNA with forensic identification and paternity tests, we now embrace genealogy genetic testing for those who are interested in how their ancestry breaks down into ethnic proportions. Genealogy testing is one of the more recent applications of DNA technology. Though genetic and medical DNA tests are used to yield different results, they share a key element - Family. One area of medical gene testing is interested in inherited diseases. You may have gotten your blue eyes from dad and a beautiful singing voice from mom, but from whom did you get your celiac disease, your asthma, your sickle cell anemia? If it runs in your family, there is a chance that molecular genetic testing will find it.
We all have that "mystery" family member that we can't quite identify when we are conducting genealogy research. The same is true with a mystery illness that may plague one or more family members. Where did it come from? Was it inherited? Can it be passed on to subsequent generations? Until recently, if you couldn't readily produce the medical history of your ancestors going back several generations, or if you were adopted, there was a slim chance of discovering whether your medical malady was just a fluke or an inherited disorder. In some cases, you may have an illness that defies traditional biochemical lab tests, biopsies, or electronic scans such as MRI (magnetic resonance imaging), PET (positron emission tomography), CAT (computerized axial tomography), or ultrasound.
DNA testing is becoming more and more a traditional go-to diagnostic, especially now that many of the tests are faster and cheaper. DNA testing identifies the molecular defects of a human inherited disease, making it easier for a doctor to diagnose such medical disorders. There are different techniques used in genetic testing, including examination of the DNA molecule, as well as the biochemical testing for gene products such as enzymes and proteins. DNA testing can be used to detect a disease before symptoms occur; to confirm a diagnose for a patient with symptoms; to discover the family history of a disease; to estimate the risk of developing certain cancers, as well as Alzheimer's disease; and finally to discern whether the genetic problem can be passed on to children.
The tests are simple and may include a blood draw, a spit test, or a buccal smear, which is nothing more than scraping the inside of your cheek with a swab to gather DNA material. There are numerous laboratories that run the tests, many of which offer direct-to-consumer (DTC) testing. According to the Centers for Disease Control and Prevention*, there are more than 2,200 diseases that can now be detected through genetic testing. Before you consider taking such a test, however, it is advisable to check out the CDC webpage on CDC genomic testing** for summaries and recommendations on the validity and utility of specific genetic tests.
A short list of hereditary diseases that can now be detected include:
Celiac (and other food sensitivities)
Duchenne muscular dystrophy
Lyme disease (in the early stages)
Sickle cell anemia
One of the hereditary diseases listed that can now be detected is celiac disease, which is a sensitivity or a complete intolerance to foods containing either wheat or gluten. This food sensitivity can cause major intestinal damage, malnutrition, osteoporosis, and impairment of other major organs, as well as joints, muscles, and nerves. Since I underwent DNA testing and was diagnosed with celiac just a few years ago, I will share my own experience to illustrate better the process of genetic testing.
Almost overnight, results of my annual bone mineral density tests began to show rapid bone loss. Though doctors could give me no diagnosis for this negative trend, they were quick to prescribe bone-building medications (oral bisphosphonates such as Fosamax, Actonel, and Boniva). I refused to go that route and instead located a holistic internist who recommended that I have a complete genetic panel done to check for food sensitivities and ultimately the celiac gene.
For someone who had never even heard of "celiac," I was stunned to receive the results. The molecular analysis turned up two genes known as HLA-DQ2 and HLA-DQ8, which indicate a predisposition to celiac. If a patient does not have the genes, then they cannot have celiac disease. Not only do I have the main gene, but I possess the non-celiac gene, as well. The fact I have two copies of the celiac indicator, means I have a stronger predisposition to gluten sensitivity and celiac disease (celiac sprue). But wait, here's where it gets exciting! These results indicate that each of my parents possessed at least one copy of a gluten-sensitive gene. That knowledge helps me better understand the medical issues my parents experienced in their later lives. That is a huge finding. The upshot: I adopted a gluten-free diet and have stopped and even reversed my bone loss by several percentage points -- without the use of drugs!
In the case of celiac, you can have one or two copies of the gene and never show any symptoms. You may never show a symptom until one day you wake up and ask "what the heck is happening to me?" Celiac has been shown to kick into gear out of the clear blue due to environmental factors, an illness, or stress. In other cases, you may be suffering the affects of a silent celiac that is causing intense internal damage without your realizing it.