Jf. Navarro et R. Espert, BIOLOGICAL BASIS OF INFANTILE-AUTISM - I - GENETIC, NEUROIMMUNOLOGICAL AND NEUROCHEMICAL ASPECTS, Psicologia conductual, 6(2), 1998, pp. 363-389
In the first part of this review paper on biological basis of infantil
e autism we describe the main genetic, neuroimmunological and neuroche
mical investigations carried out in this pathology. Twin and segregati
on analysis studies indicate that genetic factors may play a relevant
role in the etiology of autism. However, although genetic factors are
clearly involved, environmental variables must be also important. In f
act, concordance rates for autism in monozigotic twins are not of 100%
. Investigations related to autoimmunity hipothesis can be grouped int
o three broad categories. The first includes studies on the cellular e
lements of the immune system (T-cells and NK cells). The second group
concerns studies on the humoral elements of the immune system. The thi
rd category focuses on maternal-fetal tolerance and immunoreactivity s
tudies. Likewise, in this context a viral hipothesis has been proposed
to explain some cases of infantile autism. Thus, autism has been etio
logically linked to numerous prenatal infections, including rubella, c
ytomegalovirus, varicella zoster, herpes simplex and toxoplasmosis. On
the other hand, although results are still inconclusive, a serotonerg
ic dysfunction has been described in numerous patients with autism. Fu
rthermore, a functional imbalance between monoamines has been suggeste
d in this pathology. Endogenous opioids peptides have been also involv
ed in the pathogenesis of autism. According with this hipothesis, the
hyperfunction of the endogenous opioid system could explain the majori
ty of the symptoms associated with autism.