Definitions
- DNA
- DNA (desoxyribonucleic acid) is the double-stranded, helical molecular chain found within the nucleus of most cells (exception e.g. red blood cells). The DNA sequence is determined by the sequence of the nucleotides A, C, G, T (A = adenosin, C = cytosin, G = guanidin, and T = thymidin). In the DNA, there are non-coding regions and coding regions. In the coding regions of the DNA, there is the sequence that carries the information to determine the sequence of the amino acids of an entire protein. Hence, by using the information from the DNA, a cell is able to synthesize a protein.
- DNA Test
- A DNA test allows to proof or to exclude one or several variations in the DNA sequence from a coding region (gene) as well as from a non-coding region that may or may not cause changes in the function of the cell metabolism. A DNA test can be used to study the inheritance of an individual when compared with other persons that may be or may not be related (e.g. paternity test).
- Gene
- A gene is the smallest functional unit on the DNA that encodes a protein and enables cell to reproduce and perform its functions.
- Gene Test
- A gene test allows to proof or to exclude one or several variations in the DNA sequence from a coding region (gene) that may or may not cause a change in the function of the cell metabolism. As a change in the nucleotide sequence in the coding region has often a direct impact on the sequence of the protein, a gene test allows usually to predict small or large functional changes in the metabolism caused by these variations. Such variations in the metabolism can lead in childhood to a severe disease (inborn error of metabolism) or lead in adults to cardiovascular diseases, cancer or neurogenerative disorders such as Alzheimer's disease. In the low density lipoprotein gene.
- Family Tracing
- When a inherited disorder is diagnosed in a particular family, further family members can be easily tested by gene tests and the diagnosis of this disease can either be confirmed of excluded. As this strategy to identify an affected individual in such a family is very cost-effective (in autosomal-dominant disorders up to 50 percent of the first degree family members are affected) programs endorsed by the World Health Organization are being carried out in many countries. An example is the MED PED (Make Early Diagnosis - Prevent Early Death) program for familial hypercholesterolemia.
