Neurodevelopmental Abnormalities

Abstract

Neurodevelopmental abnormalities are among the most important components of fetal alcohol abuse syndrome. Information relating to these abnormalities is now voluminous; therefore, it has been divided into two chapters for purposes of presentation, beginning with microcephaly, the most readily observable of this family of neurodevelopmental disorders. It is important to bear in mind, however, that all of these abnormalities are biologically linked—they all arise from disturbances to the ectoderm, the outer surface layer of the trilaminar embryonic structure, which also gives rise to the skin, teeth, and nails. Because disturbances in these structures all arise from the same tissue layer, it is not surprising that abnormalities in these different parts of the body are clustered into what might otherwise be called an ectodermal syndrome. The fact that structures like the heart arise from the mesoderm, the middle layer of the trilaminar layer, is a possible reason that abnormalities in those organs are less common in FAS and should not be included as a formal component of FAS. Distinctions relating to specific embryological tissue origins provide construct validity for a syndrome—structures originating together are damaged together.