WEEK 1 OB FALL 2019

Genetics • Common genetic (inherited) conditions that you would counsel and screen patients either prior to pregnancy or at their first prenatal visit o A gene is a segment of DNA that is passed down from parents to children and confers a trait to the offspring.  Dad determines if the baby will be XX (girl) or XY (boy) o Genes can be either dominant or recessive. When there is both a dominant and a recessive gene in the pair, the traits of dominant gene are present.  The traits of the recessive gene are present when both genes of the pair are recessive. o Genetic diseases or disorders are usually related to a defective recessive gene and present in the developing fetus when both pairs of the gene have the same defect.  2 dominant genes will be the trait that is expressed. Genetic diseases are on the recessive genes which is a good thing because it is not as common for the parents to have the same recessive genes. o Mendelian Inheritance  Autosomal Dominant: The affected person has affected parent, there’s a 50% chance of passing the trait, males and females are equally affected (dad can pass to son).  Autosomal Recessive: Can have clinically normal parents, but both parents must be carriers, 25% chance of affected child, 50% chance child is carrier, males and females affected equally. o Common Recessive Genetic Disorders  Sickle cell anemia