Medical Genetics - V. M. Zaporozhan 2005

Methods for Diagnosing Hereditary Diseases
Molecular-Genetic Methods (DNA Diagnostic Methods)
Indications for DNA Diagnostics

Molecular-Genetic Methods (DNA diagnostic methods) constitute a large and diverse group of techniques designed to detect variations in The Structure of a target DNA region.

1. Confirmation of the clinical Diagnosis of a monogenic disorder and clarification of the mutation type. Diagnostic capabilities have advanced significantly following the Human Genome Project and the sequencing of The Human Genome. The range of Monogenic Diseases diagnosed using molecular methods and accessible via prenatal diagnosis is constantly expanding. This list includes cystic fibrosis, Duchenne-Becker muscular dystrophy, hemophilia (A and B), phenylketonuria, Hunter syndrome (mucopolysaccharidosis), adrenogenital syndrome, Huntington's disease, fragile X syndrome, among others. Today, laboratories worldwide can diagnose over 1,000 Monogenic Disorders.

2. Presymptomatic diagnosis, performed when clinical signs of a late-onset disease are absent.

3. Detection of heterozygous carriers of a mutant Gene in cases of autosomal recessive or X-linked disorders.

4. Prenatal Diagnosis of monogenic diseases.

5. Preimplantation Genetic Diagnosis.

6. Identification of genetic susceptibility to Multifactorial Diseases.

7. Personal identification (DNA fingerprinting) and paternity/kinship testing in forensic medicine.

8. Diagnosis of oncological diseases.

9. Determination of drug METABOLISM phenotypes in clinical Pharmacogenetics.

10. Diagnosis of infectious diseases (detection of pathogen DNA or RNA). Test systems for identifying the following have been developed and are now widely used in clinical practice: HIV infection (recognized as the gold standard method), hepatitis B, C, D, and E (including quantitative assays); Sexually Transmitted Infections such as chlamydiosis, ureaplasmosis, mycoplasmosis, Trichomoniasis, Gardnerellosis, Gonorrhea, and TORCH infections (Toxoplasmosis, rubella, herpes, cytomegalovirus); bronchopulmonary diseases, including tuberculosis, as well as several others. Practically any microorganism or virus can be detected in any medium using this method.

11. Determination of antimicrobial resistance in pathogens of infectious diseases. The Development of resistance is associated with Mutations in specific genes that can be identified.

12. In the future—creation of a genetic profile (passport) for any individual. This implies using automated systems to analyze the entire spectrum of mutations responsible for both monogenic and multifactorial disorders, and to assess predisposition to Cancer.