How Do I Assess a Family Tree for Inheritance Patterns?

An accurate collection and evaluation of the family history remains an important part in the clinical evaluation of every patient. Knowledge of a patient's family history is useful for diagnosis and risk assessment of relatively uncommon single-gene disorders, such as fragile X syndrome, Huntington's disease, and other disorders, inherited following the classical Mendelian patterns. Moreover, a positive family history is a major risk factor for several common diseases, including neurodegenerative disease and movement disorders. Here, we first show how to draw a pedigree, and we then use patient cases to practice in the recognition of the inheritance patterns.