Diagnosing Schizophrenia With The Help Of The Nose

While we all have our own criteria for deciding whether or not a particular behavior is "crazy," it's not so easy to put an accurate label on an individual. The determination of schizophrenia is a task that can only be accomplished by medical professionals, and there are many other conditions that create similar symptoms and have to be eliminated through a process called differential diagnosis:

• A person whose behaviors and communications suggest schizophrenia could be just experiencing a severe vitamin deficiency, particularly a deficiency of vitamin B1 (thiamine), which results in Korsakoff's psychosis.

• A person whose behaviors and communications suggest schizophrenia could have a congenital defect in the brain's ability to use an enzyme called methylenetetrahydrofolate reductase, which keeps it from being able to use certain B vitamins.
• This same person might have experienced damage to the brain, or infections in the brain, or various kinds of psychiatric illnesses that do not involve the delusions that are characteristic of schizophrenia. For instance, someone can be paranoid, distrustful of the world, but not a paranoid schizophrenic, distrustful of the world on the basis of a false belief. Or someone can suffer bipolar disorder, a condition that used to be known as manic-depressive disorder, without maintaining bizarre, unfounded beliefs about the world. Or a person can experience hallucinations, seeing, hearing, tasting, smelling, or feeling objects or people that aren't physically there, but realize they are hallucinations, and so not act on the sensory input.

Determining whether someone has schizophrenia or some other disorder can be a tedious, time-consuming, and expensive process.

The Israeli researchers took tissues samples from seven patients who had been diagnosed with schizophrenia and seven volunteers who did not have the disease. When the scientists cultured the nose cells in the lab, they found a specific kind of RNA in the cells grown from the tissue taken from the noses of schizophrenics that did not appear in the tissue taken from the noses of the volunteers who did not have schizophrenia.

The researchers took nose swabs because many neurological conditions, notably Alzheimer's disease, involve changes in the sense of smell, and it seemed plausible that nose tissue might undergo the same kinds of changes as brain tissue. The results of this study suggest that it is not really necessary to take samples specifically from the nose.

Called micro-RNA, or miRNA, this tiny snippet of genetic material only appears when someone has the disease. But why should the nose know that someone has schizophrenia?

Micro-RNA May Identify Dozens Of Diseases

It appears that these tiny bits of non-functional RNA originated with a virus. Sometime many generations ago, the the ancestor of someone who has schizophrenia was infected with a virus. The virus was made of RNA, and to multiply itself and try to take over a cell, it attached itself to the cell's DNA.

For reasons scientists don't know, this particular virus never managed to covert its target cell into a virus factory. It just got stuck in the DNA of a sperm or egg, and that sperm or egg happened to be the sperm or egg that produced a baby. When this happened, the DNA record of the virus was repeated in every cell of the child's body. DNA, in turn, forms a template for RNA, which creates specific protein sequences to make various kinds of enzymes, tissues, hormones, and so on. The DNA that originated with a virus long, long ago creates RNA that can be detected relatively easily with genetic testing.

• Micro-RNA may be a contributing factor in obesity. The body continues to make stem cells throughout life. Most of these cells are intended to replace blood cells or bone cells, but four different kinds of micro-RNA can cause a stem cell intended to become blood or bone to turn into fat.
• Micro-RNA may be a contributing factor to heart disease. When someone has a heart attack, tissue in the heart dies. The heart becomes unable to send an electrical signal through that tissue so that the top of the heart beats first and the bottom of the heart beats last in normal rhythm. Micro-RNA affects the production of conduction factors that determine how mild or severe the problem is when the heart is damaged.
• Micro-RNA may play a special role in cancer. Stem cells are created throughout life to repair tissues, but micro-RNA can cause some stem cells to become cancer stem cells, which create tissues that are resistant to treatment.
• Micro-RNA is connected with cataracts (clouding of the lens of the eye) and progressive hearing loss.

There are different kinds of micro-RNA associated with each condition. There have to be different tests for the different kinds of micro-RNA for each condition. But why is the discovery of micro-RNA important in health care?

Tiny segments of RNA can serve as an early-warning system for diseases. As the technology for rapid analysis of RNA comes on line, it will be no longer necessary to take extensive tissue samples (the definitive test for schizophrenia currently involves a brain biopsy, for example, this test never done while the patient is still alive), to spend hours eliminating other possible diagnoses, or to delay treatment. While it's the nose that "knows" the presence of schizophrenia, simple blood tests or mouth swabs may be all that is required to diagnosis many more conditions on the basis of micro-RNA.