The Beta2 Adrenergic Receptor

Polymorphisms of the Beta2 Adrenergic Receptor
The beta2 adrenergic receptor is made up of 413 amino acids. Small variations in 1 or 2 of the amino acid components of this receptor provide for 13 distinct versions, or polymorphisms. Two of these polymorphisms are known to be more active in their signaling roles, which could set the stage for over stimulation by an environmental influence. These versions of the beta2 adrenergic receptor are normal variations seen in the general population. However, two recent studies showed that the more active versions of the beta2 adrenergic receptor are found with greater frequency in nonidentical twins, where both of the children developed autism, as well as in single-birth children with autism. The more active versions were also found in their parents. The fact that the parents and other individuals who have the polymorphisms are not affected by a developmental disorder suggests that there are other factors involved. We believe these factors are environmental influences during pregnancy, from both within and outside the mother’s womb.