{"product_id":"a-rare-maoa-gene-variant-linked-to-shooting-and-stabbing-behaviors-what-the-research-means-for-patients-and-families","title":"A Rare MAOA Gene Variant Linked to Shooting and Stabbing Behaviors: What the Research Means for Patients and Families","description":"\u003cp\u003eThis study asked whether a rare variant of the MAOA gene — the 2-repeat allele — is linked to the most serious forms of violence: shooting and stabbing. Analyzing DNA and survey data from the National Longitudinal Study of Adolescent Health, researchers compared African-American men who carried the allele with men who carried other versions of the gene. Carriers had a predicted probability of about 50% (roughly 1 in 2) of having shot or stabbed someone, versus about 7% (roughly 1 in 14) for non-carriers — approximately 13 times higher odds (p\u0026lt;0.05). The findings suggest this rare gene variant may increase the risk of extreme violence independently of childhood environment, but the small sample size means the exact numbers should be interpreted with caution.\u003c\/p\u003e\n\n\u003ch1\u003eA Rare MAOA Gene Variant Linked to Shooting and Stabbing Behaviors: What the Research Means for Patients and Families\u003c\/h1\u003e\n\n\u003ch2\u003eTable of Contents\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"#ddn-key-points\"\u003eKey Points\u003c\/a\u003e\u003c\/li\u003e\n\n  \u003cli\u003e\u003ca href=\"#background\"\u003eWhy This Research Matters: The Toll of Serious Violence\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#maoa-gene\"\u003eThe MAOA Gene in Plain Language\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#study-design\"\u003eStudy Design: Who Was in the Research?\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#genotyping\"\u003eGenotyping: How DNA Was Analyzed\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#measures\"\u003eMeasuring Shooting and Stabbing Behaviors\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#findings\"\u003eKey Findings: The 2-Repeat Allele and Extreme Violence\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#discussion\"\u003eWhat the Findings Mean\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#limitations\"\u003eStudy Limitations: What This Research Could Not Prove\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#recommendations\"\u003eRecommendations: What Comes Next for Patients and Families\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#ddn-faq\"\u003eFrequently Asked Questions\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#source\"\u003eSource Information\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003c!-- ddn:keypoints:start --\u003e\n\u003ch2 id=\"ddn-key-points\"\u003eKey Points\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eIn 133 African-American males, carriers of the rare 2-repeat MAOA allele had about 50% predicted probability of shooting or stabbing, versus 7% for non-carriers.\u003c\/li\u003e\n\u003cli\u003eThe study, analyzing the Add Health dataset, found odds of shooting or stabbing were about 13 times higher in 2-repeat allele carriers.\u003c\/li\u003e\n\u003cli\u003eThe 2-repeat allele was present in 5.2% of African-American males but only 0.1% of Caucasian males in the sample.\u003c\/li\u003e\n\u003cli\u003eThis observational study does not prove the gene causes violence and cannot predict any individual's behavior.\u003c\/li\u003e\n\u003cli\u003eGenetic testing for violence risk is not supported by this research; findings need replication in separate, larger studies.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- ddn:keypoints:end --\u003e\n\n\n\u003ch2 id=\"background\"\u003eWhy This Research Matters: The Toll of Serious Violence\u003c\/h2\u003e\n\n\u003cp\u003eSerious violent crime is a pressing public health and safety concern in the United States and around the world. Each year, approximately 5 million violent victimization events occur in the U.S. alone. A large percentage of these crimes involve lethal weapons, such as guns and knives.\u003c\/p\u003e\n\n\u003cp\u003eMurder is statistically rare. Yet it remains one of the leading causes of death for adolescents and young adults. Violent acts that do not end in murder can still leave victims physically and emotionally damaged for years.\u003c\/p\u003e\n\n\u003cp\u003eThe financial burden is staggering. Some upper-limit estimates indicate that each murder costs taxpayers more than $17 million. These costs include criminal justice expenses, medical care, lost productivity, and long-term victim services.\u003c\/p\u003e\n\n\u003cp\u003eAlthough the consequences of personal violence are well known, the causes of these extreme acts remain poorly understood. Increasing evidence indicates that serious physical violence results from a complex arrangement of neurobiological, genetic, and environmental factors. These factors act individually and also together, in ways that scientists are only beginning to map.\u003c\/p\u003e\n\n\u003cp\u003eNeuroimaging research has identified structural and functional differences in offenders compared with non-offenders. These differences appear in regions of the prefrontal cortex (the brain area involved in impulse control and decision-making) and in areas of the limbic system (the brain circuits that process emotion and threat). A string of meta-analyses (statistical studies that combine results from many prior studies) has revealed that genes account for approximately 50% of the variance in antisocial behaviors and serious violence. In other words, about half of the differences between people in these behaviors are linked to genetic factors.\u003c\/p\u003e\n\n\u003ch2 id=\"maoa-gene\"\u003eThe MAOA Gene in Plain Language\u003c\/h2\u003e\n\n\u003cp\u003eDespite strong evidence that violence is highly heritable (partly passed down through genes), the precise genetic variations connected to extreme violent acts have remained elusive. The most promising candidate is the MAOA gene (monoamine oxidase A gene).\u003c\/p\u003e\n\n\u003cp\u003eThe MAOA gene is located on the X chromosome at position Xp11.23-11.4. It contains a 30 base pair (bp) variable number of tandem repeats (VNTR) polymorphism in its promoter region. That is a stretch of DNA, near the \"switch\" that turns the gene on, where a short sequence is repeated a variable number of times in different people. This is a functional polymorphism, meaning different versions of the gene are tied to different activity levels of the MAOA enzyme.\u003c\/p\u003e\n\n\u003cp\u003eThe MAOA enzyme breaks down certain neurotransmitters (chemical messengers in the brain), such as dopamine and serotonin. These chemicals help regulate mood, impulse control, and reward-seeking behavior. When the enzyme is less active, those messenger chemicals may build up, which some research links to aggression and impulsivity.\u003c\/p\u003e\n\n\u003cp\u003eResearchers usually divide the gene's many alleles (versions) into two broad groups:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLow MAOA activity alleles:\u003c\/strong\u003e the 2-repeat and 3-repeat versions\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHigh MAOA activity alleles:\u003c\/strong\u003e the 3.5-repeat, 4-repeat, and 5-repeat versions\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003ePrior research has been remarkably consistent on one point: low-activity MAOA alleles increase the risk of antisocial behaviors mainly in males who were maltreated as children. That finding, first reported by Caspi and colleagues in a landmark 2002 study, is one of the most replicated results in the genetics of antisocial behavior. The gene–environment pattern has been confirmed by meta-analyses such as Kim-Cohen and colleagues (2006). Theoretical models connecting MAOA genotype to brain functioning have also received support, though some studies (for example, Fowler and colleagues, 2007) have raised questions about how directly the gene version predicts brain enzyme levels.\u003c\/p\u003e\n\n\u003cp\u003eMost MAOA studies, however, used broad antisocial behavior scales that mix many different behaviors. Some of those behaviors are violent; many are not (for instance, truancy or theft). That approach can mask important differences between individual behaviors. A gene might be linked to certain kinds of antisocial behavior but not others.\u003c\/p\u003e\n\n\u003cp\u003eTwo earlier lines of work pointed toward the uncommon 2-repeat allele. Guo and colleagues (2008), analyzing the same national dataset, found that the 2-repeat allele predicted serious and violent delinquency in adolescence and early adulthood. They also performed a functional analysis and showed that the 2-repeat allele had lower promoter activity than the 3-repeat and 4-repeat alleles. Beaver and colleagues (2013) linked the 2-repeat allele to arrests, incarceration, and lifetime antisocial behavior.\u003c\/p\u003e\n\n\u003cp\u003eNeither of those studies examined the most extreme violent acts specifically. The current study therefore asked a direct question: is the 2-repeat allele associated with shooting and stabbing someone?\u003c\/p\u003e\n\n\u003ch2 id=\"study-design\"\u003eStudy Design: Who Was in the Research?\u003c\/h2\u003e\n\n\u003cp\u003eThe researchers used data from the National Longitudinal Study of Adolescent Health (Add Health), a nationally representative, four-wave study of American adolescents. During the 1994–1995 academic year, participants were attending 132 middle schools or high schools across the United States.\u003c\/p\u003e\n\n\u003cp\u003eThe study tracked participants over many years:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWave 1\u003c\/strong\u003e (1994–1995): in-home interviews with 20,745 adolescents and their primary caregivers\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWave 2\u003c\/strong\u003e (about 1.5 years later): 14,738 participants\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWave 3\u003c\/strong\u003e (2001–2002, early adulthood): 15,197 participants\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWave 4\u003c\/strong\u003e (2007–2008, when participants were ages 24–32): 15,701 participants\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eAt Wave 3, a subsample was genotyped (had their DNA analyzed) for several genes related to neurotransmission (chemical signaling between brain cells). Eligibility depended on whether the person was part of a sibling pair in the study. Altogether, 2,574 participants agreed to provide buccal cells (cheek swab samples) for genotyping. The genotyping was done in a coordinated effort between Add Health and researchers at the Institute of Behavioral Genetics in Boulder, Colorado.\u003c\/p\u003e\n\n\u003ch2 id=\"genotyping\"\u003eGenotyping: How DNA Was Analyzed\u003c\/h2\u003e\n\n\u003cp\u003eThe laboratory team used a variant of a previously developed assay to genotype participants for the MAOA-uVNTR polymorphism. The assay uses the polymerase chain reaction (PCR), a technique that copies specific DNA segments so they can be measured.\u003c\/p\u003e\n\n\u003cp\u003eThe resulting DNA fragments came in five sizes, each matching a distinct allele:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e291 bp — the \u003cstrong\u003e2-repeat\u003c\/strong\u003e allele\u003c\/li\u003e\n  \u003cli\u003e321 bp — the \u003cstrong\u003e3-repeat\u003c\/strong\u003e allele\u003c\/li\u003e\n  \u003cli\u003e336 bp — the \u003cstrong\u003e3.5-repeat\u003c\/strong\u003e allele\u003c\/li\u003e\n  \u003cli\u003e351 bp — the \u003cstrong\u003e4-repeat\u003c\/strong\u003e allele\u003c\/li\u003e\n  \u003cli\u003e381 bp — the \u003cstrong\u003e5-repeat\u003c\/strong\u003e allele\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eTwo independent raters scored every genotype to reduce the chance of error. The researchers then split MAOA genotypes into two groups: subjects who possessed the 2-repeat allele, and subjects who possessed any of the other alleles.\u003c\/p\u003e\n\n\u003cp\u003eThe study included males only. MAOA is X-linked, meaning the gene sits on the X chromosome. Males carry one X chromosome and therefore one copy of the gene, which makes the genotype–behavior relationship easier to examine. In addition, shooting and stabbing behaviors are carried out almost exclusively by males.\u003c\/p\u003e\n\n\u003ch2 id=\"measures\"\u003eMeasuring Shooting and Stabbing Behaviors\u003c\/h2\u003e\n\n\u003cp\u003eShooting and stabbing were measured with two related items. During each of the four waves, participants were asked whether they had shot or stabbed someone during the previous 12 months. Responses were coded dichotomously: 0 meant the person had not shot or stabbed anyone in the past year; 1 meant they had.\u003c\/p\u003e\n\n\u003cp\u003eThe researchers built two measures from those answers. The first was a lifetime measure. It indicated whether a participant had ever shot or stabbed someone across any of the first four waves of data collection. Overall, 5.6% of the sample (about 6 in 100) reported having shot or stabbed someone at some point.\u003c\/p\u003e\n\n\u003cp\u003eThe second measure tracked repeat behavior. It summed the answers across the four waves to create a score for the total number of waves in which the person reported shooting or stabbing someone:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e4.7% (about 5 in 100) reported shooting or stabbing at one wave\u003c\/li\u003e\n  \u003cli\u003e0.8% (about 8 in 1,000) reported it at two waves\u003c\/li\u003e\n  \u003cli\u003e0.1% (about 1 in 1,000) reported it at three waves\u003c\/li\u003e\n  \u003cli\u003eNo one reported shooting or stabbing at all four waves\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eThe researchers also accounted for race, which is relevant because allele frequencies differ across ancestral groups. During Wave 1, interviewers recorded which race best described each participant. The analysis included only participants who were Caucasian (white) or African-American (Black).\u003c\/p\u003e\n\n\u003ch2 id=\"findings\"\u003eKey Findings: The 2-Repeat Allele and Extreme Violence\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003eThe first finding concerned allele frequency.\u003c\/strong\u003e Previous research showed that the 2-repeat allele is much more common in some racial groups than in others. In this dataset, the allele was carried by 0.1% of Caucasian males (about 1 in 1,000) and by 5.2% of African-American males (about 1 in 19).\u003c\/p\u003e\n\n\u003cp\u003eThe researchers double-checked these frequencies using participants' self-reported race instead of interviewer-reported race. The results were nearly identical. These frequencies also parallel those reported in other samples.\u003c\/p\u003e\n\n\u003cp\u003eBecause the 2-repeat allele was so rare in Caucasian males, all subsequent analyses were limited to the African-American male subsample. After excluding cases with missing data, the final analytic sample included 133 African-American males. Of these, 6.0% (about 6 in 100) carried the 2-repeat allele. Three additional 2-repeat carriers were dropped because they had missing data on the shooting or stabbing variables.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eThe second finding concerned ever having shot or stabbed someone.\u003c\/strong\u003e The researchers estimated a binary logistic model, a statistical technique that measures how strongly a factor (the 2-repeat allele) predicts a yes\/no outcome (shooting or stabbing). The predicted probability for participants with any other genotype was 0.07 — about 7 in 100. For participants with the 2-repeat allele, the predicted probability was 0.50 — about 50 in 100, or 1 in 2.\u003c\/p\u003e\n\n\u003cp\u003eIn plain terms, the statistical model predicted that half of the 2-repeat carriers would report having shot or stabbed someone, compared with about 7% of non-carriers. The effect was statistically significant (b = 2.56, SE = 0.79, OR = 12.89, p \u0026lt; 0.05). An odds ratio (OR) of 12.89 means the odds of shooting or stabbing were about 13 times higher in carriers. The p-value below 0.05 means the probability that this finding occurred by random chance is less than 5%.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eThe third finding concerned repeat offending.\u003c\/strong\u003e The researchers tested whether the 2-repeat allele predicted the total number of waves in which a participant reported shooting or stabbing. Because that count was highly skewed (most people had zero), they used a negative binomial regression, a technique designed for such count data.\u003c\/p\u003e\n\n\u003cp\u003eThe predicted rate of change was 0.10 for participants with other genotypes and 0.63 for participants with the 2-repeat allele. The parameter estimates showed this association was statistically significant (b = 1.87, SE = 0.54, exp(b) = 6.51, p \u0026lt; 0.05). An exponentiated coefficient (exp(b)) of 6.51 means the expected count of waves with shooting or stabbing was about 6.5 times higher for carriers.\u003c\/p\u003e\n\n\u003cp\u003eThe researchers corrected all equations for the clustering of observations within families, using the \"cluster\" command in STATA 10.0. Cases missing a family identification number were dropped from the analyses.\u003c\/p\u003e\n\n\u003ch2 id=\"discussion\"\u003eWhat the Findings Mean\u003c\/h2\u003e\n\n\u003cp\u003eThe study produced two key findings. First, carriers of the 2-repeat allele of MAOA were significantly more likely than carriers of all other alleles to report having shot or stabbed someone at least once in their lifetime. Second, the 2-repeat allele was also related to the total number of waves in which a person reported shooting or stabbing. In short, the 2-repeat allele confers an increased risk of shooting and stabbing multiple victims over the life course.\u003c\/p\u003e\n\n\u003cp\u003eTo the authors' knowledge, this is the first study to link a specific genetic polymorphism to shooting and stabbing behaviors and to having multiple shooting and stabbing victims. The finding also challenges how genetic studies have traditionally classified MAOA alleles.\u003c\/p\u003e\n\n\u003cp\u003eAlmost all prior research pooled the 2-repeat allele together with the 3-repeat allele into a single \"low activity\" category. The results of this study suggest that approach may be misguided. The most powerful effects may reside specifically within the 2-repeat allele. Combining it with the 3-repeat allele may dilute, or attenuate, the main effect of MAOA.\u003c\/p\u003e\n\n\u003cp\u003eIndeed, supplemental analyses (not reported in detail in the paper) revealed that when the 2-repeat and 3-repeat alleles were combined into one group, that combined genotype was unrelated to the odds of shooting or stabbing someone. That finding underscores how much information can be lost when distinct alleles are lumped together.\u003c\/p\u003e\n\n\u003cp\u003eThe effects seen here were independent of environmental factors. That stands in stark contrast to much of the existing MAOA research, which has shown effects largely in the presence of environmental liabilities such as childhood maltreatment. One possible explanation: the 2-repeat allele may have independent effects, whereas the 3-repeat allele may only matter when paired with an environmental risk factor. Future research will need to explore this possibility in much greater detail.\u003c\/p\u003e\n\n\u003ch2 id=\"limitations\"\u003eStudy Limitations: What This Research Could Not Prove\u003c\/h2\u003e\n\n\u003cp\u003eThe authors were careful to list several important limitations. First, all existing research on the 2-repeat allele and antisocial behavior has analyzed the same dataset: Add Health. The current study extends previous work by focusing on extremely violent behaviors, but it is not a completely independent replication of the earlier findings by Guo and colleagues and Beaver and colleagues. New studies in different samples are needed.\u003c\/p\u003e\n\n\u003cp\u003eSecond, the study examined a rare event in a small sample, with a low base rate of the 2-repeat allele. Although the findings were statistically significant, they could have been influenced by small changes in the cell sizes of the 2-by-2 table — the table that cross-tabulates the 2-repeat allele against shooting\/stabbing. Readers should exercise appropriate caution when interpreting the exact values presented in the paper.\u003c\/p\u003e\n\n\u003cp\u003eThird, the analyses were confined to African-American males. That restriction was necessary because so few Caucasian males carry the 2-repeat allele (0.1% in this sample) that multivariate statistical models could not be calculated for them. Approximately 5.5% of African-Americans and less than 1% of Caucasians carry this rare allele, according to prior studies. Future research will need sufficiently large samples to detect small-to-moderate effects of the 2-repeat allele across racial and ethnic groups.\u003c\/p\u003e\n\n\u003cp\u003eFinally, this was an observational genetic association study, not a controlled experiment. It demonstrates a statistical link between a gene variant and behavior in one dataset. It does not prove that the gene causes anyone to shoot or stab, and it cannot predict any individual person's behavior. Genes are only one piece of a very complicated puzzle that includes brain development, life experience, and social context.\u003c\/p\u003e\n\n\u003ch2 id=\"recommendations\"\u003eRecommendations: What Comes Next for Patients and Families\u003c\/h2\u003e\n\n\u003cp\u003eFor families and individuals, this research does not support genetic testing for violence risk. The 2-repeat allele is rare, the study sample was small, and the findings have not yet been replicated in an independent dataset. A single gene variant cannot tell anyone whether a particular person will commit a violent act.\u003c\/p\u003e\n\n\u003cp\u003eFor the scientific community, the authors offer a clear research agenda. The most urgent need is to examine the 2-repeat allele's effects in samples distinct from Add Health. Studies should examine African-Americans, Caucasians, and other racial and ethnic groups simultaneously, with sample sizes large enough to provide statistical power.\u003c\/p\u003e\n\n\u003cp\u003eThey also call for a change in analytic habits. Researchers should stop automatically collapsing the 2-repeat allele into a broad \"low activity\" group with the 3-repeat allele. Treating each allele separately may reveal effects that have been hidden in past work.\u003c\/p\u003e\n\n\u003cp\u003eThe authors note that it would be premature to speculate about the role of the 2-repeat allele in explaining any well-known crime trends. Until more studies are completed, the practical takeaways are about research design, not about predicting or labeling individuals.\u003c\/p\u003e\n\n\u003cp\u003eFor patients and families affected by violence, the key message is one of cautious context. This study adds to a growing body of evidence that extreme violence emerges from a complex mix of genes, brain function, and environment. No single gene predestines a person to violence, and research like this is a step toward understanding — not a basis for judgment or stigma.\u003c\/p\u003e\n\n\u003c!-- ddn:faq:start --\u003e\n\u003ch2 id=\"ddn-faq\"\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003ch3\u003eWhat did the study find about the 2-repeat allele and shooting or stabbing?\u003c\/h3\u003e\n\u003cp\u003eResearchers found that African-American males with the 2-repeat allele had a predicted probability of about 50% of having shot or stabbed someone, compared to about 7% for those with other alleles. This means roughly 13 times higher odds, statistically significant in this small sample.\u003c\/p\u003e\n\u003ch3\u003eDoes having the 2-repeat allele mean a person will commit violence?\u003c\/h3\u003e\n\u003cp\u003eNo. This is an observational study showing a statistical link in one dataset, not proof that the gene causes violence. Genes are only one piece of the puzzle. The study cannot predict any individual person's behavior, and the authors stress that no single gene predestines violence.\u003c\/p\u003e\n\u003ch3\u003eShould I get genetic testing to see if my child or I might be violent?\u003c\/h3\u003e\n\u003cp\u003eNo, this research does not support genetic testing for violence risk. The 2-repeat allele is rare, the study sample was small, and findings have not been replicated in an independent dataset. No test can tell whether a particular person will commit a violent act.\u003c\/p\u003e\n\u003ch3\u003eWhy was the study limited to African-American males?\u003c\/h3\u003e\n\u003cp\u003eBecause the 2-repeat allele is very rare in Caucasian males, affecting only about 0.1%, the sample was too small for statistical models. In this dataset, 5.2% of African-American males carried it. So all analyses focused on African-American males to have enough carriers to examine.\u003c\/p\u003e\n\u003ch3\u003eWhat were the main limitations of this study?\u003c\/h3\u003e\n\u003cp\u003eThe study used a small sample with a rare event, so exact numbers might shift with even small changes. All existing 2-repeat allele research uses the same Add Health dataset, so it is not an independent replication. Findings are not confirmed in other groups or samples.\u003c\/p\u003e\n\u003ch3\u003eShould I get a second opinion if genetic testing suggests a MAOA 2-repeat allele could make me or my family member violent?\u003c\/h3\u003e\n\u003cp\u003eNo. Genetic testing for violence risk is not supported by current research on the MAOA 2-repeat allele. The allele is rare, was studied in a small sample from one research dataset, and the findings have not been independently replicated. Even in that research, a single gene variant was not able to predict whether any individual person would shoot or stab someone. This type of research is observational, so it cannot prove that a gene causes anyone's behavior. A second opinion cannot change those limitations. Diagnostic Detectives Network provides independent expert second opinions.\u003c\/p\u003e\n\u003c!-- ddn:faq:end --\u003e\n\n\u003ch2 id=\"source\"\u003eSource Information\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003eOriginal article title:\u003c\/strong\u003e allele of the MAOA gene confers an increased risk for shooting and stabbing behaviors\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors:\u003c\/strong\u003e Kevin M. Beaver (Florida State University and King Abdulaziz University), J. C. Barnes (University of Texas at Dallas), and Brian B. Boutwell (Sam Houston State University)\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eJournal:\u003c\/strong\u003e Psychiatric Quarterly, Volume 85, pages 257–265 (2014). Published online December 11, 2013, by Springer Science+Business Media New York. DOI: 10.1007\/s11126-013-9287-x\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eData source:\u003c\/strong\u003e The National Longitudinal Study of Adolescent Health (Add Health), designed by J. Richard Udry, Peter S. Bearman, and Kathleen Mullan Harris, and funded by grant P01-HD31921 from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, with cooperating funding from 17 other agencies.\u003c\/p\u003e\n\u003cp\u003e\u003cem\u003eThis patient-friendly article is based on peer-reviewed research. It is provided for educational purposes and does not constitute medical or genetic counseling advice.\u003c\/em\u003e\u003c\/p\u003e","brand":"DiagnosticDetectives.Com","offers":[{"title":"Default Title","offer_id":47560937210012,"sku":null,"price":0.0,"currency_code":"USD","in_stock":true}],"url":"https:\/\/diagnosticdetectives.com\/zh\/products\/a-rare-maoa-gene-variant-linked-to-shooting-and-stabbing-behaviors-what-the-research-means-for-patients-and-families","provider":"DiagnosticDetectives.Com","version":"1.0","type":"link"}