Written in our genes

Astrology has long been a topic of interest in society, dating back to the Babylonians and the Greeks. More recently, Millennials and Gen Z have led a resurgence in its popularity. We continue to be enthralled by the idea that some otherworldly source knows everything about us simply from our date of birth. But are the stars truly able to foretell avid details about your personality and major life events? Enter: genetics. Genetics is somewhat similar to a horoscope — it tells you all about yourself and can be interpreted to predict different events throughout your life. While there may not be any scientific support behind zodiac signs and their influence on personality, season of birth is a prominent factor when it comes to gene expression.

Researchers at Columbia University developed an approach called Season-Wide Association Study (SeaWAS) that investigated associations between birth month and various diseases within a sample population taken from Columbia University Medical Center’s patient records. They then pulled out any traces of correlation between birth month and disease in existing literature and used previous studies as a comparison to assess the quality and accuracy of SeaWAS results. Remarkably, SeaWAS found associations between birth month and thirty-six conditions. SeaWAS was then replicated to establish birth month trends in twenty of the associated conditions, such as asthma, attention deficit hyperactivity disorder (ADHD), and reproductive performance. However, the remaining sixteen brought novel connections between conditions including atrial fibrillation, congestive cardiac failure, and coronary arteriosclerosis. Nine of the newfound associations are cardiovascular-related, six of which share a high-risk peak in March and April. This calls forth the idea that specific disease categories may have intrinsic trends of high-risk birth months.

Seasonal patterns within these conditions can all be traced back to circannual variation within white blood cells and the overall immune system. More than 4000 protein-coding mRNAs have seasonal expression profiles in white blood cells, adipose tissue, and within the cellular composition of blood. Interleukin-6 (IL6) receptor complex and C-reactive protein (CRP) are two biomarkers for risk of cardiovascular, psychiatric, and autoimmune diseases that have shown increased levels of expression during European winter, suggesting a pro-inflammatory immune response.

“Nine of the newfound associations are cardiovascular-related, six of which share a high-risk peak in March and April.”

Xaquin Castro Dopico and his team of researchers at the University of Cambridge hypothesized that Artnl expression would also follow a seasonal expression pattern. Artnl (Bmal1), a clock gene, influences circadian rhythms and has been shown to influence psychiatric disorders. When studied in mice, the knockdown of Bmal1 in the mammalian circadian timing system led to behavioral abnormalities that are linked to depression and anxiety disorders. When comparing samples from the United Kingdom, Australia, and the United States, Artnl was found to have seasonal variability. It was found to have peaks in its expression during summer months, followed by troughs in winter months, lining up with the onset of seasonal affective disorder. In mice, Artnl controls the number of monocytes within the immune system and while Artnl’s effect on the human immune system is not known, monocytes have the highest levels during winter in Europeans, when Artnl expression is at its lowest. It is possible the combined effects of lower levels of Artnl, as well as higher expressions of IL6 and CRP have an influence on the increased frequency of cardiovascular disease-associated deaths in European winter.

How can we apply this formative data to make a difference in the way we approach these diseases? Preventative medicine is at the forefront of the healthcare industry. With further research into seasonal variation’s influence on gene expression and related diseases, we may be able to use these trends in treatment plans. Cancer is consistently the second-leading cause of death for Americans but is generally treatable when caught in early stages. However, most people don’t discover they have cancer until it has progressed into other organs, at which point very little can be done. By combining birth trends with existing risk factors found through genetic testing, we can advance our understanding of true risk factors for disease development and improve overall patient prognosis. Additionally, it has been suggested that season of inoculation may influence the success or quality of a vaccine response. This research also has the potential to improve diabetes treatments, immune response variability, cardiac risk factors, neuropsychiatric symptoms, and more. Zodiacs and birth trends can allow one to feel aligned with the stars, but they have only been theorized as a cause of real diseases. While learning about “genetic horoscopes,” be sure not to treat these trends as laws.