Medical Genetics - V. M. Zaporozhan 2005

Prevention of Hereditary Diseases
Prenatal Treatment of Certain Hereditary Diseases and Malformations

Currently, Methods for intrauterine Treatment of certain Hereditary diseases and fetal malformations have been developed.

For instance, successful cases of fetal surgery have been reported for diaphragmatic hernia, certain Urinary Tract anomalies, teratomas, and lung cysts (performed via open or, whenever possible, closed hysterotomy, such as needle aspiration).

Prenatal treatment is also performed for the virilizing form of adrenogenital syndrome. Pregnant women at high genetic risk of having a child with this condition are prescribed low doses of dexamethasone starting at 4-5 months of embryonic development. It suppresses androgen secretion by the embryonic Adrenal Glands and prevents adrenal hyperplasia. Concurrently, Prenatal Diagnosis of the condition is essential (chorionic villus sampling or another invasive method followed by molecular genetic Analysis of the sample). If the fetus is male or healthy, treatment is discontinued. If the fetus is a female, treatment is continued until the end of Pregnancy, thereby preventing The Development of virilization. After birth, lifelong glucocorticoid replacement therapy is administered.

In cases of alloimmune thrombocytopenia and other hematologic disorders, Procedures such as fetal platelet transfusion or exchange transfusion have been documented. For fetal arrhythmias, cardiac medications are prescribed; for methylmalonic acidemia, the administration of Vitamin B12 has proven successful; and for multiple carboxylase deficiency, biotin therapy is used.

Today, a new clinical discipline is emerging — fetology (from Latin *fetus* — fetus), which focuses on studying the fetus as a patient. As a precursor to neonatology, this branch of medicine aims to study Human Development throughout the entire prenatal period, investigate the Etiology AND Pathogenesis of various pathological conditions, and provide their Diagnosis and treatment.

In the future, as Gene Therapy methods become safer and more effective, the primary focus of treating hereditary diseases will likely shift to the antenatal period. The promise of this approach lies in the immunological tolerance characteristic of the fetus; when foreign Cells are introduced into fetal Tissues, the fetus recognizes them as its own. Furthermore, early gene therapy can prevent the onset of symptoms associated with hereditary disorders.

In the future, the widespread use of stem cells for treating Hereditary and Congenital pathologies during the antenatal period may also become possible.