Is This a Causal Relationship? Mendelian Randomization as a Statistical Method for Unraveling Connections

Mendelian Randomization (MR) is a powerful statistical tool to infer a causal relationship between the presence of genetic variants and different traits and phenotypes.^, It is particularly useful when trying to elucidate causal relationships between exposures and outcomes based on observational data. This method bases itself on the principle of randomness of how genetic variants might segregate during the process of meiosis, the Mendelian principle of independent assortment.

Since past decades, as our knowledge about the genetic architecture of human beings has been enhanced, the challenge is to understand how genetic variants may contribute to the development of phenotypes and traits. We have learned from this growing comprehension that as the genetic complexity of a specific trait rises, it may be less inheritable, and our predictive power reduces.

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