genetics
[jĕ-net´iks] the branch of biology dealing with the phenomena of heredity and the laws governing it.
biochemical genetics the study of the fundamental relationships between genes, protein, and metabolism. This involves the study of the cause of many specific heritable diseases. These include those resulting from the improper synthesis of hemoglobins and protein, such as
sickle cell disease and
thalassemia, both of which are hereditary anemias; some 200 inborn errors of metabolism, such as
phenylketonuria and
galactosemia, in which lack or alteration of a specific enzyme prohibits proper metabolism of carbohydrates, proteins, or fats and thus produces pathologic symptoms; and genetically determined variations in response to certain drugs, for example, isoniazid.
clinical genetics the study of the causes and inheritance of genetic disorders. In addition to the diseases mentioned under biochemical genetics, other aspects of clinical genetics include the study of chromosomal aberrations, such as those that cause mental retardation and
down syndrome, and immunogenetics, or the genetic aspects of the
immune response and the transmission of genetic factors from generation to generation.
Many pediatric hospital admissions involve genetic disorders. In obstetrics and neonatal medicine, prenatal diagnosis of genetic defects and improvement of pre- and perinatal conditions are a major concern. In adults, such diseases as breast cancer, coronary artery disease, hypertension, and diabetes mellitus have all been found to have predisposing genetic components that are relevant to identification of risk factors and early diagnosis.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.