Genetic Evidence, MAOA, and State v. Yepez

This amicus brief offers two main contributions. First, we describe how MAOA studies based on the prior “candidate-gene approach” are unreliable due to inherent flaws in the methodology, leading to inconsistencies in replication. Second, the general scientific consensus has emerged that the earlier MAOA studies (upon which the defense experts relied) are now an outdated method of studying psychiatric genetics. Third, to the extent that recent studies adopting the more rigorous genomewide association studies (GWAS) have attempted to replicate the earlier findings of MAOA candidate-gene studies, they have found no reliable correlation between MAOA and violence.