From genotype to phenotype

Abstract

During the last years, genetic tests have been commonly used in clinical practice. Difficult and doubtful diagnoses are frequent and to date many clinicians have needed geneticists for the study of specific genes and gene panels (through next generation sequencing) to reach a reliable diagnosis. The identification of genes and mutations related to a disease, together with the development of faster and cheaper methodologies, has led to a better basic understanding of several diseases, giving clinicians new opportunities for the management of many genetic diseases. However, these important results also showed that genetics is not always conclusive. Indeed, different phenotypic expressions (diseases) are due not only to sequence variants of the genome (mutations). It is increasingly clear that epigenetic factors have an important influence through complex mechanisms of regulation. This field of study is relatively new and the mechanisms involved in the regulation of gene expression are largely unknown.