Preface: Molecular Genetics and Pediatrics

Adaptive processes, initially during fetal life, subsequently in infancy and childhood followed by adolescence and adulthood characterize each stage of life. The steady state of adulthood culminates in an irreversible pathway central to the process of aging. These phenomena highlight the role of development as the imprinting process that defines the phenotype of the individual in health and disease. The uniqueness of the person and the specificity of ones experiences within the environment are a consequence of the phylogenetic past, the freedoms and constraints imposed by development, maturation and aging.

The organism’s response to the indifferent environment is the quintessential reason for biological variation. In the gamete, variation may involve harmless base pair substitutions, extending to profound changes such as chromosomal loss. With fertilization the newly formed zygote is impacted by selective forces, which, if they are favorable, will improve the organism’s adaptation to the environment. Thus, disease arises when homeostatic changes, which occur as a consequence of selective forces that enhance variation and survival, are incongruent with the environment – a failure of adaptation.

Mutations and variations in gene structure result in altered gene expression, thus, producing birth defects and heritable diseases of metabolism that may alter growth, development and neurological function. This issue presents advances in molecular genetics that highlight these fundamental concepts.