Is there an ADHD gene?

The alleles of the genes behind the genetic component of ADHD are unknown.

The Gene

It is an interesting question but even associating a gene or allele mutation with development of ADHD symptoms or intelligence is an ill-posed question.  There are too many variations and outside influences to even predict.  It’s like the “butterfly effect” where everything is an influence but how much and what the role is on the outcome is highly variable.