genetics and its approach in the diagnosis of diseases with familial history

in general, both common illnesses and rare diseases can develop in people and their relatives in families. therefore, taking family history is an effective screening tool to detect such diseases and patients should be aware of its importance in families’ health with updating information in regular visiting. for more information on identifying the genetic pattern of diseases, in this article, we will first explain the evidence for genetic similarities within and between human populations and the human genetic variation. then, we will address the importance of medical counseling and pedigree drawing and will clarify the necessity of biological samples and their collection in human genetic studies.