The low activity form of the MAOA gene (MAOA-L) has been linked to increased levels of aggression and violence. Data from a 2007 study suggests that MAOA-L individuals are hypersensitive, so are affected more by negative experiences (thus react more aggressively in defence) as opposed to being hyposensitive, and lacking emotion for harming others. Male members of a large Dutch kindred displaying abnormal violent behaviour were found to have low MAO-A activity linked to a deleterious point mutation in the 8th exon of the gene. The unaffected male members within the family did not carry this mutation. The first study that investigated behaviour in response to provocation showed that, overall, MAOA-L individuals showed higher levels of aggression than MAOA-H (high MAOA activity) subjects. There was also strong evidence for a gene-by-environment interaction as both groups showed similar low levels of aggression with low provocation, but MAOA-L individuals displayed significantly higher levels of aggression in a high provocation situation. A further gene-by-environment interaction was found in a long-term study performed on large number of children. Those with the MAOA-L genotype paired with maltreatment in childhood were correctly predicted to commit crime. Similar results are replicated in the majority of other related studies, but not all.