MEDICAL BIOLOGY, ANATOMY, HUMAN PHYSIOLOGY AND PATHOLOGY - Ya.I. Fedonyuk 2010

BIOLOGY

SECTION 1. BIOLOGICAL FOUNDATIONS OF HUMAN VITAL ACTIVITY

1.4. ONTOGENETIC LEVEL OF LIFE ORGANIZATION

1.4.2. Fundamentals of Human Genetics

MEDICAL Genetic Counseling

Medical genetic counseling (MGC) is a specialized healthcare service primarily aimed at preventing the birth of children with Hereditary and Congenital disorders in a family. The MAIN OBJECTIVES OF MGC are: 1) establishing an accurate Diagnosis of a hereditary disease; 2)

determining the mode of Inheritance of the disease in the given family; 3) calculating the recurrence risk of the hereditary disease in the family; 4) identifying the most effective Prevention strategy; 5) explaining the gathered information, genetic prognosis, and prevention Methods to the counselees.

MGC is conducted in four stages: 1) establishing a diagnosis; 2) formulating a prognosis; 3) drawing Conclusions; 4) providing recommendations to the family on preventing the birth of an affected child.

At The First stage, the clinical diagnosis is refined using Genetic Methods. At the Second Stage, the probability of having an affected child (genetic risk) is prognosticated. Prognostication depends on the mode of inheritance. For Mendelian (monogenic) diseases, genetic risk assessment is calculated based on Mendel's Laws; for polygenic diseases, it is primarily based on empirical data, i.e., actual observations. At the Third Stage, the geneticist provides a Conclusion with recommendations regarding the degree of genetic risk. A genetic risk of up to 5% is classified as low and is not considered a contraindication to childbearing in the family. A risk ranging from 6% to 20% is considered moderate. In this case, recommendations depend on the magnitude of the genetic risk, the medical and social consequences of the pathology, and the availability of prenatal Diagnostics. If the genetic risk exceeds 20% and methods for Prenatal Diagnosis of the condition are unavailable, future childbearing is not recommended. At the Fourth Stage, the geneticist provides advice on preventing the birth of an affected child.

A fundamentally important task of MGC is to find simple and accessible methods for detecting heterozygous carriers of mutant genes, and to perform Differential diagnosis to rule out phenocopies and new Mutations. Practically every couple should undergo MGC before planning a Pregnancy (prospectively) and mandatory after the birth of an affected child (retrospectively). Mandatory MGC should be conducted in high-risk families presenting with the following indications:

1) birth of a child with a congenital malformation;

2) diagnosed or suspected hereditary disease in the family;

3) developmental delay or mental retardation in a child;

4) recurrent spontaneous miscarriages or stillbirths;

5) consanguineous marriages;

6) exposure to teratogens or suspected teratogenic factors During the first three months of pregnancy;

7) adverse pregnancy course.

To provide medical genetic counseling in Ukraine, a specialized healthcare infrastructure exists within the public health system (attached to outpatient clinics and hospitals) known as the medical genetic service. It comprises 53 interdistrict medical genetic offices (IMGOs) and one municipal office, 18 regional medical genetic consultations (RMGCs), and 7 interregional medical genetic centers (IRMGCs in Kyiv, Lviv, Kharkiv, Kryvyi Rih, Crimea, Donetsk, and Odesa). In 1992, the Ukrainian Scientific Center of Medical Genetics was established under the Ministry of Health and the Academy of Medical Sciences of Ukraine. This center, along with the Lviv Research Institute of Hereditary Pathology, was entrusted with coordinating all areas of the medical genetic service in Ukraine. The activities of the entire medical genetic service are directed by the Coordination Council on Medical Genetics under the Ministry of Health (MoH) of Ukraine and the Chief Specialist of the MoH of Ukraine. Specialized care for patients with Hereditary diseases is also provided by specialists from specialized research institutes of the MoH of Ukraine, departments of higher medical educational institutions, and postgraduate medical institutes.