RT Book, Section A1 Pyeritz, Reed E. A2 Papadakis, Maxine A. A2 McPhee, Stephen J. A2 Rabow, Michael W. A2 McQuaid, Kenneth R. SR Print(0) ID 1193140250 T1 Family History & Pedigree Analysis T2 Current Medical Diagnosis & Treatment 2023 YR 2023 FD 2023 PB McGraw-Hill Education PP New York, NY SN 9781264687343 LK accessmedicine.mhmedical.com/content.aspx?aid=1193140250 RD 2024/03/28 AB The first step in considering how important genetic factors might be in the clinical situation of a patient is obtaining a detailed family history. At a minimum, a patient should be queried in detail about all first-degree relatives—parents, siblings, and offspring—(age, sex, health status if alive, including major illnesses; cause of death) and more distant relatives with reference to the particular condition at issue. Ethnicity of both sides of the family should be noted; any disorders known to be especially prevalent in a particular ethnic group should be asked about specifically. Once the family history is obtained, it should be analyzed; medical geneticists and genetic counselors are trained in this task and are particularly valuable when the busy clinician has neither the time nor the staff to pursue the information. A pedigree diagram (eg, eFigure 40–3) with the symbols filled in to indicate the presence of a condition can be instructive in suggesting a mode of inheritance. Once targeted genetic testing of the proband produces a result, the diagram also proves useful in identifying relatives who might benefit from counseling about similar testing.