Answer from: Maria José Mendiola, MD, MSc in Human Genetics, MSc in Science Communication, ObGyn
Multifactorial inheritance refers to the pattern of inheritance for health conditions caused by both genetic and other factors. In addition to genetics or inherited ones may include diet, lifestyle, aging, contact with other toxins. Multifactorial conditions do not always develop even when there is a genetic mutation that increases a person’s chance of developing health conditions, for example, and not a woman who has an inherited breast and ovarian cancer gene mutation will develop breast or ovarian cancer. The mutation or variant is not completely penetrant so the reason for incomplete penetration of the condition is most likely to the mixture of information in the gene mutation with the information in one or more other genes as well as other other causes like environment. Some of the health conditions and differences from birth are well understood and there may be genetic testing available to determine whether a person has a gene mutation which increases their chances of developing the conditions. Some multifactorial conditions could be, for example, cancer, metabolic as diabetes, high blood pressure, heart disease, high cholesterol, some neurological conditions so psychiatry like schizophrenia, alzheimer’s and some muscular diseases like arthritis, osteoporosis or some respiratory diseases that is very common, for example, like asthma or allergies that could be linked to the multifactorial conditions.
Answer from: Douglas Lester, PhD, MSc, BSc (Hons)
Examples of multifactorial fertility disorders are endometriosis and polycystic ovary syndrome. So neither of these conditions can be caused by a single gene defect. They haven’t got a single gene for endometriosis or polycystic ovary. Instead, environmental and many different gene variants are probably responsible for the diseases; it’s very complicated. I believe there is another company out there that looks at hundreds of genes from endometrial tissue. They look at the number of hundreds of genes and whether some are more expressed than others and some less expressed; it’s a very complicated story for endometriosis. As far as our company, it’s not possible to develop a reliable genetic DNA test, which will predict whether someone will definitely develop either of these conditions.
