Federal Indictment in Zarutska case
Is There a Genetic Link to Violence? Revisiting Brunner’s Syndrome and MAOA Variants
October 23, 2025 — Charlotte, NC
The man accused of fatally stabbing Ukrainian refugee Iryna Zarutska on a Charlotte light rail train has now been indicted on federal charges and could face the death penalty. According to and , Decarlos Brown Jr., 34, was charged with “violence against a railroad carrier resulting in death” — a federal offense that makes him eligible for capital punishment. The attack, which claimed the life of 23-year-old Zarutska, has reignited national debates around crime, immigration, and the deeper roots of violent behavior.
But beneath the headlines lies a more uncomfortable question: Are there biological or genetic predispositions to violence that society refuses to confront?
Fox News via MSN,
Decarlos Brown Jr., 34, who was accused of fatally stabbing the Ukrainian woman on a Charlotte light rail train, has been indicted by a federal grand jury, per ABC News.
On Wednesday, the jury charged Brown with violence against a railroad carrier and mass transportation system resulting in death, which is a capital offense under federal law.
Brunner’s Syndrome and the Genetics of Aggression: Rethinking Behavioral Predisposition
In light of recent headlines surrounding violent crime and federal indictments, renewed attention is being paid to the biological underpinnings of aggression. While environmental factors such as poverty, trauma, and social instability are widely acknowledged, a growing body of research continues to explore whether certain genetic markers may also play a role in behavioral predisposition.
One of the most studied examples is Brunner’s Syndrome, a rare genetic condition first identified in the Netherlands in 1992. The disorder is linked to a mutation on the X chromosome that disrupts the production of monoamine oxidase A (MAOA) — an enzyme critical for regulating neurotransmitters like dopamine, serotonin, and norepinephrine. These chemicals influence mood, impulse control, and aggression.
The syndrome was named after the study’s author H.G. Brunner of Radboud University in the Netherlands.
The Brunner Study: A Genetic Case for Behavioral Disturbance
The original study, titled “X-Linked Borderline Mental Retardation with Prominent Behavioral Disturbance”, documented a Dutch family in which several male members exhibited unusually high levels of impulsive and violent behavior, including arson and attempted sexual assault. Genetic analysis revealed a mutation that severely reduced MAOA activity, leading to abnormal neurotransmitter levels and cognitive impairments.
This discovery sparked a wave of research into the role of MAOA variants in broader populations. Scientists began investigating whether certain alleles — especially the low-activity versions — might correlate with increased risk for antisocial behavior.
MAOA and the 2R Allele: A Controversial Correlation
h/t Slideserve
In 2012, criminologists Kevin M. Beaver of Florida State University and Michael G. Vaughn published findings in Comprehensive Psychology suggesting that the 2R allele of the MAOA gene was disproportionately present among individuals with histories of violent behavior.
Their study found that 5.2% of Black participants carried the 2R allele, compared to 0.1% of white participants. While the sample size and methodology have been debated, the data raised difficult questions about how genetic predisposition intersects with race, environment, and social outcomes.
Importantly, researchers caution against deterministic interpretations. Genes do not act in isolation — they interact with upbringing, community, and personal experience. The presence of a risk allele does not guarantee violent behavior, nor does its absence ensure peaceful conduct.
Another study that was funded by the NIH in 2015, study author S. Sohrabi, gave further evidence of a strong genetic link to violent crime,
The criminal gene: the link between MAOA and aggression (REVIEW)
One emerging aspect of recent advances in neurocriminology is the discovery of possible links between violent criminal behaviour and genetics. Analysis of data from several studies indicates that the strongest link between genetic variation and aggression comes from monoamine oxidase A (MAOA); a gene encoding an enzyme responsible for catabolising amine neurotransmitters such as dopamine, serotonin and noradrenaline. In this work, we present a critical review of the data available from recent investigations regarding the impact of an allelic variation of the MAOA gene on criminal behaviour.
Conclusions,
Deficiencies in MAO-A activity have been identified in numerous studies to correlate positively with aggressive behaviour, but its influence may be moderated by environmental factors. Although further research into this aspect of neurocriminology is required, the findings highlight an ethical dilemma with regards to prosecuting criminals.
Ethical dilemma and Scientific Responsibility
The study of behavioral genetics is fraught with ethical complexity. While understanding biological risk factors could inform early intervention and mental health support, it also risks reinforcing stereotypes or being misused in policy debates. Most geneticists and ethicists advocate for a careful, context-sensitive approach that prioritizes individual dignity and avoids racial essentialism.
Rather than framing these findings as evidence of inherent group differences, many scholars argue for a biosocial model — one that integrates genetic data with environmental stressors, trauma exposure, and socioeconomic conditions.
Others, less bound by what some describe as ideological constraints, advocate for a more open scientific dialogue — one that includes exploring potential genetic and neurological differences across populations.
Toward a More Informed Future
As science continues to probe the neurological and genetic roots of behavior, society faces a critical challenge: how to responsibly integrate this knowledge into public discourse, criminal justice, and mental health policy. The goal is not to stigmatize, but to understand — and ultimately to build systems that support resilience, reduce harm, and promote equity.
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