Patterns of Inheritance

The Patterns of Inheritance course provides a foundational understanding of how genetic information is passed from parents to children and why this knowledge is essential for risk assessment, genetic counseling, and patient care. The course begins with a clear review of DNA, genes, and chromosomes before moving into Mendelian inheritance — the classic principles discovered by Gregor Mendel. Learners will explore dominant and recessive inheritance patterns, understanding how a single copy of a variant gene can cause a condition (dominant) versus when two copies are required (recessive). Visual diagrams and Punnett square exercises will show probabilities of inheritance in real-life scenarios, helping learners explain risk to patients with accuracy and confidence.

From there, the course covers autosomal inheritance (conditions that are not related to sex chromosomes) and sex-linked inheritance (X-linked and Y-linked conditions). Special attention is given to X-linked recessive disorders, which disproportionately affect males (e.g., hemophilia, Duchenne muscular dystrophy) and to how carriers can transmit variants without showing symptoms. The course also explores more complex patterns such as codominance (where both alleles are expressed, as in ABO blood groups), incomplete dominance, mitochondrial inheritance (passed through maternal line), and multifactorial inheritance (where both genes and environment play a role, such as in diabetes or heart disease).

Learners will also be introduced to de novo mutations (variants that occur spontaneously and are not inherited from parents), mosaicism (where some but not all cells carry a variant), and imprinting disorders (where expression depends on whether the gene came from the mother or father). These sections emphasize why some genetic conditions cannot be predicted by simple Mendelian ratios.

This course ties directly to Natera’s carrier screening (Horizon) and prenatal testing (Panorama) solutions by showing how identifying a carrier status in one partner informs risk for recessive conditions in a future pregnancy, and why partner testing is recommended. Learners will practice interpreting pedigree charts, identifying inheritance patterns in sample family trees, and calculating recurrence risks.

Interactive content includes case studies where participants analyze family history data to determine whether a condition is autosomal dominant, recessive, or X-linked, and make recommendations for testing or counseling. The course also provides strategies for explaining these concepts to patients in simple, empathetic language — empowering them to make informed reproductive choices.

By the end of this course, learners will be able to: define and differentiate major inheritance patterns, construct and interpret basic pedigrees, calculate probabilities for various outcomes, recognize when a condition follows a Mendelian pattern versus a complex one, and know when to escalate to genetic counseling or further testing. This knowledge is critical for providers, nurses, genetic counselors, and support staff who work with Natera’s genetic testing products, ensuring they can guide patients with clarity and confidence.