Behavioral sciences are inseparably related to genetics. A variety of neurobehavioral phenotypes
are suggested to result from genomic variations. However, the contribution of genetic factors
to common behavioral disorders (i.e. autism, schizophrenia, intellectual disability) remains to be understood
when an attempt to link behavioral variability to a specific genomic change is made.
Probably, the least appreciated genetic mechanism of debilitating neurobehavioral disorders is somatic
mosaicism or the occurrence of genetically diverse (neuronal) cells in an individual’s brain. Somatic
mosaicism is assumed to affect directly the brain being associated with specific behavioral patterns.
As shown in studies of chromosome abnormalities (syndromes), genetic mosaicism is able to change
dynamically the phenotype due to inconsistency of abnormal cell proportions. Here, we hypothesize
that brain-specific postzygotic changes of mosaicism levels are able to modulate variability of behavioral
phenotypes. More precisely, behavioral phenotype variability in individuals exhibiting somatic
mosaicism might correlate with changes in the amount of genetically abnormal cells throughout the
lifespan. If proven, the hypothesis can be used as a basis for therapeutic interventions through regulating
levels of somatic mosaicism to increase functioning and to improve overall condition of individuals
with behavioral problems.