Are Mental Illnesses Inheritable?

The question of whether mental illness is genetic tends to be a complicated discussion. It is most likely caused by a combination of genetic and environmental factors. Conditions like depression and schizophrenia tend to be more closely related to genetics than some other disorders. There is still much to be explored between the relationship of mental illness and genetics. However, it is usually caused by a combination of four main factors: genetics, environmental, psychological, and biological factors. While there is no current genetic test to determine if you carry a specific gene that is likely to lead to a specific mental illness, one's best bet is to review their familial line to determine their genetic risks for developing a mental illness. With this being said, if you do have a close family member with a particular illness that does not mean you will develop it, there is just an increased risk.  

Focusing specifically on depression, it is one of the most common mental illnesses that affects nearly 350 million people around the world. The genetic components of this condition are still being explored, however it is heavily involved with genes that regulate neurotransmitters (like serotonin transporter genes). Overall chemical imbalances, childhood trauma, life stressors and drug and alcohol abuse can also contribute to the development of mental illnesses. While we still have a lot we don’t know, there are links between genetics and mental illnesses. By studying more about these contributing factors, we can learn how to manage our mental illnesses and live a balanced life.  

Childhood Food Allergies Caused by a Combination of Genetic and Environmental Factors

Researches have found a link to child food allergies and genetic factors along with environmental factors. A specific combination of environmental factors and genetic factors can trigger infant and childhood food allergies. In order to trigger these allergies a child would have to have genetics that change the skin absorbency, have been exposed to infant wipes that leave soap on the skin, and have been exposed to allergens such as dust or food allergens. Joan Cook-Mills is a professor of allergy-immunology at Northwestern University Feinberg School of Medicine and was the lead researcher on this study. She explained ways to prevent these environmental factors, which when combine with the genetic factors can cause childhood allergies. She said to, “Reduce baby’s skin exposure to the food allergens by washing your hands before handling the baby. Limit use of infant wipes that leave soap on the skin. Rinse soap off with water like we used to do years ago.” The soap in the wipes disrupts the skin barrier. This link between environmental and genetic factors that causes food allergies was discovered through clinical evidence of food allergies in humans and tests were done using neonatal mice models. The clinical evidence showed 35% of the children that were looked at who were looked at with food allergies, also had dermatitis. Dermatitis is caused by three different gene mutations that reduce the skin barrier. This study is helping to understand food allergies and how they develop which is important to know for developing more responsive medicine. Cook-Mills’ goal is to discover interventions that will more effectively respond to signals and block the development of food allergies.

Closer Links to the Genetics of Fraternal Twins

The chance of having fraternal twins has long been known to increase if relatives have also had the  event occur, however researchers have recently been underway to find a closer link to the explanation. The United States alone saw a 76% increase in the fraternal twin population from 1980 to 2011, and scientists want an answer.

This article explains the path scientists have taken to identify the increasing factor. They've collected and compared single nucleotide polymorphisms (SNPs) of 2000 mothers of fraternal twins to SNPs of mothers who had not had twins. Researchers narrowed the results down to find two SNPs that increase a woman's likelihood of having fraternal twins by about 30%!

One of the SNPs is known to cause an increase in the hormone involved in the production of follicles, which are the sites within the ovaries that house and mature the eggs before they are released from the ovary. If the levels of this hormone is too high, the mother has an increased chance of releasing multiple eggs.

The second SNP is a bit more complicated. This one in particular is a gene that alters the way molecules signal to each other. This gene in turn, called SMAD3, has an affect on the way that the ovaries respond to the hormone coded by the other SNP. This same gene has also been linked to osteoarthritis. Scientists are planning to conduct further research on how mothers react differently due to the SMAD3 gene. These results presented were only the first step.

It's really awesome that this group of scientists have made such progress on identifying the genetic components behind having fraternal twins. This is the closest that scientists have yet to come in relation to this subject matter. This is not exactly the most critical research to be done, as there usually aren't complications or anything wrong with birthing fraternal twins. However its still always great to hear about the evolution of genetic findings in all aspects of life.