Preliminary results support the exploration of brain structural features as endophenotypes for neurodevelopmental disorders. Two studies in autism found limbic structures in unaffected first-degree relatives were more similar to affected family members than healthy controls (Dalton, Nacewicz, Alexander, & Davidson, 2007; Rojas et al., 2004). Children with ADHD and their unaffected siblings both had decreases in right pre-frontal gray and matter and left occipital gray and white matter compared with healthy controls; however, cerebellar abnormalities were found only in the children with ADHD (Durston et al., 2004). Specific areas of the cortex were different in healthy monozygotic twins of individuals with schizophrenia compared to unrelated controls, suggesting some abnormalities in cortical thickness were related to disease state and other to genetic liability (Cannon et al., 2002; Gogtay et al., 2003). A recent meta-analysis concluded that there was evidence of decreased gray matter volume and hippocampal abnormalities in first-degree relatives of individuals with schizophrenia (Boos, Aleman, Cahn, Pol, & Kahn, 2007). The scope of the conclusions was limited, however, by the few brain structures in which enough data was available for
