Genetics is the study of inheritance with many overlapping concepts. Classical genetics studies genes that form the basis for inherited physical traits such as eye color. Cytogenetics looks at the structure of chromosomes in a karyotype obtained before birth in amniotic fluid, and afterwards in blood. Molecular genetics looks at the fine structure of alleles of every gene encoded in nucleic acid base pairs of the DNA double helix. DNA transcribed into RNA forms a mirror image or blue print of the genes, which like a manufacturing code for the production of all body proteins, gives precise directions for protein molecule production and assembly. Errors anywhere along the way beginning due to inherited or spontaneous mutations can lead to illness, especially when it concerns the nervous system. The desire to learn about our human nature led to the human genome project with the ability now for each person to see their entire gene pool in a print out of alleles associated with health and disease. Owning your genetics begins with knowing it.
Simply stated, it is the reason why both children in a family each with shared DNA encoding a propensity to fight off recurring bacterial infection due to common variable immune deficiency or CVID, later develop the autoimmune disease, PANDAS or PANS. Similarly, why 2 of 3 children in a family, each descended from a single parent carrying the HLA disease alleles for Celiac disease, are great candidates for a gluten-free diet to offset development of the disease. More correctly, knowing whether you carry your sister or mother’s disease-producing gene that caused her multiple sclerosis should lead you to seek the best defense through a brain healthy program to modify your risk. Knowing your genetics can be the best defense for optimal brain health.
In fact, the observation by researchers that infectious diseases had an inherited element was not new, nor was the observation that individuals respond differently to particular infections. Likewise, the genes involved in our protective immunity have been under greater selective pressure resulting from infectious diseases. Which is why researchers have focused on human leukocyte antigen (HLA) genes, encoded on chromosome 6 where the blueprint of the immune system resides. HLA genes shows an unusually high rate of polymorphisms or gene variation when compared with other areas of the genome, indicating that we have evolved to combat infectious microbes, and when deficient, genetics may be the leading factor in losing the battle with them. Comprised of class I-III, class I HLA genes encode how we primitively respond to infection with an innate immune response that brings antigens of the microbe to the surface of cells that engulf them. By contrast, class II genes encode activation of the adaptive immune system composed of T-cells and B-cells and antibodies against antigen attackers, while preserving immune tolerance self-antigens throughout the body. The Loss of tolerance to self-antigens is the starting point of three autoimmune diseases, arthritis, diabetes, and Celiac disease that only subsides with an integrated immune based therapy program to reset the targets of the HLA immune system.
The importance of genetics to infectious and autoimmune disorders has recently come with appreciation of the human microbiome defined as the collection of microorganisms that reside within our body, and previously overlooked as determinants of health and disease. Research is now focusing on disease-causing or pathogenic organisms, employing molecular genetic sequencing techniques and other using molecular tools to extract and compare bits of a particular kind of ribosomal RNA or rRNA.
Given the appearance of new microbial agents, and the everyday occurrence of unexplained lethal neurological syndromes, we are presently at crossroads to make gigantic gains in our knowledge of how microbes affect health, transitioning from description to causality and microbial engineering. Would it surprise you to learn that all healthy individuals carry endogenous retrovirus sequences as an integral part of the human genome? It is only after viral insertion of one additional envelope gene encoding certain viral membrane proteins that mediate budding of virus particles to the cellular receptors, that the disease called AIDS begins.
The true capability of such microbes residing in our body to cause human disease is probably best exemplified in post-infectious autoimmune illness when resident and invasive microbial agents obtain the capacity to trigger our immune system, turning it on and off at will. With more than 90% of cells in the human micobiome of bacterial, viral, parasitic, fungal or otherwise non-human in nature, and human metabolism and immunity attributed to the molecular genetic contribution of microbial and human interaction, human beings can rightfully be termed superorganisms.
The appreciation of genetics has also yielded insights into other mechanisms of autoimmune brain disease such as the newly recognized axis of communication between the gut and brain discovered by genetic studies and called the mind-gut connection that accounts for the spectrum of psychiatric symptoms attributed to a leaky gut and irritable bowel.
Whether healthy and at risk or in the throws of an illness, genetic is turning out to be a guidepost for a plan of action to retake your immune system and body integrity.