PRA in the Cardigan Welsh corgi, termed rod - cone dysplasia 3 (RCD3), is also caused by a mutation in a subunit of cGMP phosphodiesterase, this time the alpha subunit, which results in a disease with
a comparable age of onset to RCD1 [4].
Researchers found that levels
of severity, functional impairment, and patterns
of comorbidity among the additional 3.46 %
of children who met all
of the ADHD criteria except
age of onset under 7 were
comparable with those
of other mental and behavioral disorders.
Two studies have identified groups
of girls exhibiting chronically high levels
of antisocial behavior across childhood and early adolescence and having an increased risk for continued antisocial behavior.60 In addition, Odgers and several colleagues found that 7.5 percent
of all girls between the
ages of seven and fifteen displayed an early -
onset of offending that persisted into adolescence and that this pattern was similar to boys
of the same
age.61 Other studies suggest that although strongly aggressive behavior in girls before the
age of seven is rare, continuity
of offending for such girls may be stronger than that among
comparable boys and that such early problem behavior in girls should be considered a significant warning sign
of potential future problems.62