Patterns of Inheritance
PRINCIPLES OF MENDELIAN INHERITANCE Print Section Listen Mendelian disorders result from a mutation at a single genetic locus. A locus may be present on an autosome or on a sex…
Preconception Counseling
INTRODUCTION Print Section Listen Case 1: Ms. Meckel is a 25-year-old whose first and only pregnancy ended in a full-term normally grown infant with a large skin-covered encephalocele. The infant…
Common Chromosomal Abnormalities
INTRODUCTION Print Section Listen Case 1: A 25-year-old patient presents to you for counseling. She underwent chorionic villus sampling and the chromosomal analysis revealed trisomy 21. How do you counsel…
Taking a Family History
INTRODUCTION Print Section Listen Case 1: A 30-year-old G3P2 presents for her new OB visit at 10 weeks’ gestation. She has had two full-term uncomplicated vaginal deliveries. Her second child,…
Organization and Structure of Human Chromosomes
INTRODUCTION Print Section Listen The human genome is comprised of nuclear DNA sequences, tightly packed into distinct subunits called chromosomes and hundreds to thousands of circular DNA molecules within the…
Gene Structure and Function
INTRODUCTION Print Section Listen Knowledge of the genetic basis of health and disease has increased dramatically in the last 20 years. The first draft of the sequence of the human…
