Because of computer technologies, genetics has benefited during the past 20 years from specific and complex explanations of the mechanisms leading to genetic syndromes and diseases. Genetic syndromes are complex occurrences with genotype aberrations, with or without observable (phenotypic) characteristics, that can seriously affect the normal life of individuals. Embryological and fetal anomalies (abnormalities) that may or may not include genetic defects, are classified as individual anomalies (e.g., malformation, disruption, deformation, dysplasia), and pattern anomalies (e.g., associations, sequences, syndromes, and developmental field defects). With computers, statistical analyses of such diseases can be accomplished easily, including evaluation of the frequency of a single malformation in the presence of a genetic disease, or in complex processes such as genetic transmission analysis (linkage studies), and multivariate analyses of patterns and risk factors.

Linkage is the occurrence of two or more genes (genetic...