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Learn MorePathological Genetics: How Genes Cause Disease
Pathological Genetics: How Genes Cause Disease
Master the genetic basis of human disease, from point mutations and Mendelian disorders to cancer and pharmacogenomics
Role Play
Created byISO Horizon
Last updated 6/2026
English
What you'll learn
- Classify mutations by type and predict their effects on protein structure and function
- Distinguish loss-of-function, gain-of-function, dominant negative, and haploinsufficiency mechanisms
- Recognize the four classical Mendelian inheritance patterns from pedigrees and clinical presentations
- Identify hallmark single-gene disorders including Huntington, Marfan, cystic fibrosis, and Duchenne muscular dystrophy
- Explain how numerical and structural chromosomal abnormalities produce syndromes like Down, Turner, and DiGeorge
- Apply the multifactorial and polygenic frameworks to common diseases like diabetes and heart disease
- Describe the genetic and epigenetic basis of cancer, including hereditary syndromes like BRCA and Lynch
- Interpret pharmacogenomic principles for high-stakes drug-gene interactions
- Discuss the ethical and practical dimensions of genetic counseling, prenatal screening, and newborn screening
- Evaluate emerging gene and RNA-based therapies transforming the treatment of inherited disease
Explore related topics
Course content
22 sections • 33 lectures
- What Pathological Genetics Actually Studies6:53Welcome to the field that explains why a single misplaced nucleotide can derail an entire organism. In this lecture you will learn how pathological genetics sits at the intersection of molecular biology, medicine, and clinical reasoning, asking not just what genes do but what happens when they fail. You will see how the discipline differs from classical genetics by focusing on disease mechanisms rather than inheritance patterns alone, and how it differs from molecular pathology by zooming out from the cell to the whole patient. Expect a clear definition of key terms like genotype, phenotype, penetrance, and expressivity, plus a walk-through of how clinicians and researchers reason from a DNA change to a clinical syndrome. By the end you will understand why this field has become central to modern medicine, from rare pediatric disorders to common adult diseases, and why every healthcare professional benefits from speaking its language.
- Types of Mutations: A Visual Catalog9:47Mutations come in many flavors, and recognizing them is the first step toward predicting disease. This lecture walks you through the full spectrum, starting with point mutations and their three subtypes — silent, missense, and nonsense — then moving to insertions and deletions, the frameshift chaos they often produce, and the in-frame variants that quietly swap or remove amino acids. You will explore trinucleotide repeat expansions that grow across generations, large structural rearrangements like translocations and inversions, and copy number variations that duplicate or delete entire stretches of DNA. Each mutation type is paired with a concrete clinical example so the abstract becomes tangible. You will also learn the standard nomenclature used in genetic reports, so when you encounter a notation like c.1521_1523delCTT or p.Phe508del, you can decode exactly what change occurred and where.
- From DNA Change to Protein Dysfunction10:31A mutation in DNA only matters because of what it does to a protein, and this lecture traces that journey step by step. You will follow how different mutation types ripple through transcription, splicing, and translation to produce proteins that are truncated, misfolded, mislocalized, or simply absent. Learn how missense changes can subtly alter active sites or binding interfaces, how nonsense mutations trigger nonsense-mediated decay to eliminate the transcript entirely, and how splice site disruptions can scramble the reading frame in unpredictable ways. The lecture also introduces protein quality control systems like the unfolded protein response and proteasomal degradation, explaining why some mutant proteins accumulate toxically while others are simply degraded. By connecting molecular change to functional outcome, you build the intuition needed to predict whether any given variant is likely to cause disease.
- Loss-of-Function vs Gain-of-Function Mutations9:34Not all mutations break a protein in the same way, and the distinction matters enormously for understanding disease. This lecture contrasts loss-of-function mutations, where the protein product is reduced or absent, with gain-of-function mutations, where the protein acquires a new or enhanced activity that harms the cell. You will examine classic examples on both sides, including loss-of-function in tumor suppressor genes and gain-of-function in oncogenes like RAS. The lecture explains why loss-of-function mutations are usually recessive while gain-of-function mutations tend to be dominant, and how this rule shapes pedigree analysis. You will also see edge cases where a single gene can produce either phenotype depending on the specific variant, illustrating why molecular characterization, not just gene identification, drives modern diagnosis and treatment.
- Dominant Negative Effects and Haploinsufficiency8:39Two of the most clinically important mutation mechanisms deserve their own focused treatment, and this lecture delivers it. Haploinsufficiency occurs when a single functional copy of a gene cannot produce enough protein to meet cellular needs, and you will learn why this matters for dose-sensitive genes involved in development, transcription factor networks, and structural proteins. Dominant negative effects are subtler and often more devastating, occurring when a mutant protein actively interferes with the function of the wild-type protein, frequently by forming defective multimeric complexes. You will see how this mechanism explains the severity of conditions like osteogenesis imperfecta and certain forms of Marfan syndrome. The lecture closes by showing how distinguishing these two mechanisms guides decisions about therapeutic strategies, from gene replacement to allele-specific silencing.
- Penetrance, Expressivity, and Genetic Modifiers9:16Genotype rarely maps cleanly to phenotype, and this lecture explains why two people with the identical mutation can have wildly different clinical outcomes. You will learn the precise definitions of penetrance, the probability that a mutation produces any disease phenotype, and expressivity, the degree to which it does so. The lecture explores age-dependent penetrance using examples like Huntington disease and BRCA-associated cancers, then turns to variable expressivity through neurofibromatosis type 1, where café-au-lait spots in one patient may coexist with severe tumors in their relative carrying the same allele. You will also meet genetic modifiers, environmental triggers, and stochastic developmental events that shape the phenotype around a primary mutation, building a more realistic mental model of how genes and life experience intersect.
- Section 1 Quiz: Foundations of Genetic Pathology
- Roleplay: Foundations of Genetic Pathology
- Autosomal Dominant Disorders: Huntington Disease9:10Huntington disease is the textbook autosomal dominant disorder, and this lecture uses it to illuminate the entire inheritance pattern. You will learn how a CAG trinucleotide repeat expansion in the HTT gene produces a toxic gain-of-function protein that progressively destroys neurons in the striatum, causing the characteristic triad of motor, cognitive, and psychiatric symptoms. The lecture explains why a single mutant allele is enough to cause disease, the phenomenon of anticipation where repeat lengths expand across generations, and the inverse relationship between repeat number and age of onset. You will also see how Huntington disease became a paradigm for genetic counseling, predictive testing ethics, and the challenges of caring for patients with adult-onset incurable conditions. Expect concrete pedigree examples that train your eye to spot vertical transmission and the roughly fifty percent recurrence risk that defines this pattern.
- Autosomal Dominant Disorders: Marfan and Familial Hypercholesterolemia10:15Two more autosomal dominant conditions reveal the diversity of mechanisms that can produce a dominant pattern. Marfan syndrome arises from mutations in FBN1 encoding fibrillin-1, with most variants acting through a dominant negative effect that destabilizes connective tissue and produces the classic skeletal, ocular, and cardiovascular features including aortic root dilation. Familial hypercholesterolemia, in contrast, illustrates haploinsufficiency, where loss of one LDL receptor copy doubles serum cholesterol and dramatically accelerates atherosclerosis. You will see how these two diseases, both dominantly inherited, demand entirely different therapeutic strategies, and how recognizing the underlying mechanism shapes screening, treatment, and family counseling. The lecture also introduces the concept of pleiotropy, where a single gene affects multiple organ systems, using Marfan as the prototypical example.
- Autosomal Recessive Disorders: Cystic Fibrosis12:32Cystic fibrosis is the most common life-shortening autosomal recessive disease in populations of European descent, and this lecture uses it to anchor your understanding of recessive inheritance. You will learn how mutations in the CFTR gene impair chloride transport across epithelial membranes, producing thick mucus that obstructs airways, pancreatic ducts, and the reproductive tract. The lecture details the most common mutation, F508del, and explains how different CFTR variants fall into functional classes that now guide personalized therapy with CFTR modulators. You will also examine carrier frequency, the calculation of recurrence risk in couples, the role of population screening, and the surprising heterozygote advantage hypotheses that may explain why such a damaging allele has persisted. Pedigree patterns showing horizontal transmission and consanguinity are explored in detail.
- Autosomal Recessive Disorders: Sickle Cell Disease and PKU10:14Two more recessive disorders showcase different molecular themes and powerful lessons in evolutionary genetics and newborn screening. Sickle cell disease arises from a single missense mutation that converts glutamate to valine in beta-globin, causing hemoglobin polymerization under low oxygen and producing the rigid sickled red cells responsible for vaso-occlusive crises and chronic hemolysis. You will learn why this allele is maintained at high frequency in malaria-endemic regions through heterozygote advantage. Phenylketonuria, by contrast, is an enzyme deficiency disorder where loss of phenylalanine hydroxylase activity allows toxic accumulation of phenylalanine, producing intellectual disability unless dietary intervention begins in infancy. PKU illustrates the triumph of newborn screening and the principle that genetic disease can sometimes be prevented entirely with environmental modification.
- X-Linked Disorders: Duchenne Muscular Dystrophy and Hemophilia10:08X-linked inheritance produces some of the most clinically distinctive pedigrees in medicine, and this lecture explores two flagship examples. Duchenne muscular dystrophy results from loss-of-function mutations in the enormous dystrophin gene, leading to progressive muscle degeneration that typically affects boys, with onset in early childhood and loss of ambulation by adolescence. You will learn how Becker muscular dystrophy represents a milder allelic variant where partial dystrophin function is preserved. Hemophilia A and B, caused by deficiencies in clotting factors VIII and IX respectively, illustrate how X-linked disease manifests with bleeding diatheses and how carrier females can occasionally show symptoms due to skewed X-inactivation. The lecture explains why males are typically more severely affected, how females can be obligate carriers, and the characteristic pattern of affected maternal uncles that often points to X-linked transmission.
- Mitochondrial Inheritance and Heteroplasmy8:42Mitochondrial DNA follows rules unlike any other genome, and this lecture walks you through them with clinical examples. You will learn that mitochondrial mutations pass exclusively from mother to all her children, never from father to offspring, producing pedigrees with a distinctive matrilineal pattern. The concept of heteroplasmy, where mutant and wild-type mitochondrial genomes coexist within a cell, explains why the same mutation can produce wildly different phenotypes depending on the mutant load in each tissue. The lecture covers landmark mitochondrial diseases including Leber hereditary optic neuropathy, MELAS, and Leigh syndrome, showing how tissues with the highest energy demands like the central nervous system, heart, and skeletal muscle are most vulnerable. You will also encounter the threshold effect and tissue mosaicism that complicate diagnosis and counseling.
- Section 2 Quiz: Single-Gene Disorders and Mendelian Inheritance
- Roleplay: Single-Gene Disorders and Mendelian Inheritance
- Numerical Abnormalities: Down Syndrome9:30Trisomy 21 is the most common viable autosomal aneuploidy in humans, and this lecture uses Down syndrome to teach the fundamentals of numerical chromosomal disease. You will learn how meiotic nondisjunction produces an extra copy of chromosome 21, how maternal age increases this risk, and how rarer mechanisms like Robertsonian translocations and mosaicism can produce clinically indistinguishable presentations with very different recurrence risks. The lecture details the characteristic phenotypic features including craniofacial findings, hypotonia, congenital heart defects, and intellectual disability, while emphasizing the wide variability in expression. You will also explore the gene dosage hypothesis explaining why a third copy of a small chromosome produces such profound effects, and the implications for prenatal screening using cell-free fetal DNA and ultrasound markers like nuchal translucency.
- Sex Chromosome Aneuploidies: Turner and Klinefelter9:25Sex chromosome aneuploidies are usually compatible with life but produce distinctive phenotypes that every clinician should recognize. Turner syndrome, characterized by a single X chromosome and absence of a second sex chromosome, produces short stature, gonadal dysgenesis, characteristic neck webbing, and cardiovascular anomalies including coarctation of the aorta. You will learn why most 45,X conceptions are not viable and how mosaicism shapes the clinical spectrum. Klinefelter syndrome, with karyotype 47,XXY, produces tall stature, hypogonadism, gynecomastia, and often subtle cognitive findings, with diagnosis frequently delayed until evaluation for infertility. The lecture explains X-inactivation and why an extra X chromosome still produces phenotypic effects through escape genes, and surveys other variants like 47,XYY and 47,XXX with their generally milder presentations.
- Structural Chromosomal Abnormalities9:28Beyond gains and losses of whole chromosomes, the architecture of individual chromosomes can be rearranged in ways that cause or predispose to disease. This lecture walks you through deletions, where segments are lost, duplications, where they are copied, inversions, where they flip orientation, and translocations, where pieces exchange between chromosomes. You will learn the critical distinction between balanced rearrangements, which often produce no phenotype in the carrier but threaten their offspring, and unbalanced rearrangements that immediately produce disease. The Philadelphia chromosome resulting from a translocation between chromosomes 9 and 22 illustrates how rearrangements can create oncogenic fusion proteins like BCR-ABL, driving chronic myeloid leukemia and pioneering targeted therapy with tyrosine kinase inhibitors.
- Microdeletion and Microduplication Syndromes12:18Some of the most clinically important chromosomal disorders are too small to see under a microscope and require molecular techniques to detect. This lecture explores microdeletion syndromes including 22q11.2 deletion syndrome, also known as DiGeorge or velocardiofacial syndrome, which produces cardiac defects, immune deficiency, hypocalcemia, and characteristic facial features. You will also meet Williams syndrome from 7q11.23 deletion with its distinctive cocktail party personality, Prader-Willi and Angelman syndromes from 15q11-q13 abnormalities, and Smith-Magenis syndrome. The lecture explains how nonallelic homologous recombination between low-copy repeats drives these recurrent rearrangements, why the same genomic region can produce reciprocal deletion and duplication syndromes with different phenotypes, and how chromosomal microarray analysis revolutionized diagnosis of developmental disorders.
- Uniparental Disomy and Imprinting Effects8:36Inheriting both copies of a chromosome from a single parent is rare but can produce striking disease, and this lecture explains how. Uniparental disomy occurs when both members of a chromosome pair come from one parent, either through meiotic errors followed by trisomy rescue or through other mechanisms. You will learn how this matters most for chromosomes containing imprinted genes, where maternal and paternal copies are expressed differently. Prader-Willi syndrome and Angelman syndrome both arise from disruptions in chromosome 15q11-q13 but produce completely different phenotypes depending on whether the maternal or paternal contribution is affected, illustrating the principle of genomic imprinting in its most clinically vivid form. The lecture provides a foundation for understanding why parent of origin matters in genetic disease.
- Section 3 Quiz: Chromosomal Disorders
- Roleplay: Chromosomal Disorders
- Multifactorial Inheritance: Beyond Mendel10:18Most common diseases do not follow Mendelian inheritance, and this lecture introduces the framework needed to understand them. You will learn how multifactorial inheritance arises from the combined effects of many genetic variants, each with small individual contributions, interacting with environmental exposures across a lifetime. The lecture explains the liability threshold model, where disease appears only when genetic and environmental risk factors push an individual past a critical threshold, and shows how this model predicts patterns like increased recurrence in close relatives, higher concordance in identical than fraternal twins, and elevated risk after a more severely affected proband. Concrete examples like cleft lip and palate, neural tube defects, and pyloric stenosis bring the abstract framework to life and connect it to clinical risk assessment.
- Genome-Wide Association Studies and Polygenic Risk12:19Modern genetics has identified thousands of common variants associated with common diseases, and this lecture explains the techniques and concepts behind them. You will learn how genome-wide association studies scan the genomes of large populations to find single nucleotide polymorphisms that occur more often in cases than controls, and how this approach has implicated specific loci in everything from type 2 diabetes to schizophrenia. The lecture introduces polygenic risk scores, which combine the effects of many variants into a single estimate of disease susceptibility, and discusses both their promise for personalized prevention and their limitations, including poor performance across ancestries when scores are derived primarily from European populations. You will leave with a clear sense of where common variant genetics succeeds and where it still falls short.
- Gene-Environment Interactions8:57Genes do not act in isolation, and this lecture explores how environmental factors modulate genetic risk in clinically important ways. You will see classic examples including how PKU patients escape disease entirely with dietary restriction, how G6PD deficiency only causes hemolysis after exposure to specific drugs or foods like fava beans, and how alpha-1 antitrypsin deficiency produces emphysema dramatically faster in smokers. The lecture explains the concept of differential susceptibility, where the same variant can be protective or harmful depending on context, and explores how exposures like diet, stress, infection, and toxins shape the expression of genetic predispositions. You will gain a richer understanding of why genetic determinism is misleading and why prevention strategies must account for both nature and nurture.
- The Genetic Basis of Diabetes and Heart Disease9:03Two of the leading causes of morbidity worldwide have substantial but complex genetic underpinnings, and this lecture unpacks them. For type 2 diabetes, you will learn how variants in genes like TCF7L2 contribute modest individual risk that combines with obesity, diet, and inactivity to drive the global epidemic, while monogenic forms like MODY illustrate how single-gene defects in beta cell function can mimic common diabetes. For cardiovascular disease, the lecture explores how familial hypercholesterolemia represents the monogenic extreme, how common variants near genes like PCSK9 and APOE modify lipid levels and atherosclerosis risk, and how polygenic risk scores are beginning to identify individuals who benefit most from early intervention. The genetic architecture of these diseases illustrates the full spectrum from monogenic to polygenic.
- Genetic Susceptibility in Autoimmune and Psychiatric Disease11:27Some of the most heritable common diseases involve the immune system and the brain, and this lecture explores their genetic landscapes. Autoimmune conditions including type 1 diabetes, rheumatoid arthritis, and multiple sclerosis show strong associations with specific HLA alleles, and you will learn how these molecules shape the risk of immune attack on self-tissues. The lecture also surveys variants outside the HLA region that contribute to autoimmunity and explains why autoimmune diseases often cluster in families and individuals. For psychiatric disorders including schizophrenia, bipolar disorder, and autism spectrum disorders, you will see how heritability estimates are high but identifying specific causal variants has been challenging, with both rare large-effect mutations and many common small-effect variants contributing to risk.
- Section 4 Quiz: Complex Inheritance and Multifactorial Disease
- Roleplay: Complex Inheritance and Multifactorial Disease
- Epigenetic Mechanisms in Disease10:10Genetic information is more than just DNA sequence, and this lecture introduces the chemical marks and chromatin states that regulate gene expression without changing the underlying code. You will learn how DNA methylation typically silences genes, how histone modifications create permissive or repressive chromatin environments, and how non-coding RNAs add another layer of regulation. The lecture explains how epigenetic patterns are established during development, maintained through cell division, and sometimes inherited across generations. You will see how disruption of these mechanisms contributes to disease, from developmental syndromes caused by mutations in epigenetic regulators to the widespread epigenetic reprogramming that drives cancer. This foundation prepares you to understand imprinting disorders, tumor epigenetics, and the emerging field of epigenetic therapy.
- Imprinting Disorders: Prader-Willi and Angelman Syndromes10:50Genomic imprinting produces some of the most fascinating disorders in human genetics, and this lecture explores them in depth. You will learn how a small subset of human genes are expressed from only one parental allele, with the other silenced by epigenetic marks established in the parental germline. Prader-Willi syndrome results from loss of paternally expressed genes on chromosome 15q11-q13, producing hypotonia in infancy followed by insatiable hunger, obesity, and intellectual disability. Angelman syndrome arises from loss of the maternally expressed UBE3A gene in the same region, producing severe intellectual disability, ataxia, seizures, and characteristic happy demeanor. The lecture also covers Beckwith-Wiedemann and Russell-Silver syndromes, showing how imprinting errors at chromosome 11p15 produce opposite growth phenotypes.
- Oncogenes and Tumor Suppressors11:08Cancer is fundamentally a genetic disease, and this lecture establishes the two major categories of cancer-relevant genes. Oncogenes are mutated versions of normal proto-oncogenes that drive cell proliferation when activated, and you will see how gain-of-function mutations in genes like RAS, MYC, and BRAF push cells toward uncontrolled growth. A single activating mutation in one allele is typically sufficient, making oncogene mutations dominant at the cellular level. Tumor suppressor genes, in contrast, normally restrain proliferation or maintain genomic integrity, and disease results when both copies are inactivated, illustrated by TP53, RB, and APC. The lecture explains Knudson's two-hit hypothesis using retinoblastoma as the classic example and shows how this framework predicts the inheritance patterns of hereditary cancer syndromes.
- DNA Repair Defects and Genomic Instability9:58The integrity of the genome depends on a sophisticated network of repair pathways, and defects in these systems profoundly increase cancer risk. This lecture surveys the major repair mechanisms including mismatch repair, nucleotide excision repair, base excision repair, and the homologous recombination and non-homologous end joining pathways that handle double-strand breaks. You will learn how inherited defects in mismatch repair genes cause Lynch syndrome with elevated risk of colorectal and endometrial cancer, how BRCA1 and BRCA2 mutations impair homologous recombination and predispose to breast and ovarian cancer, and how xeroderma pigmentosum results from defective nucleotide excision repair with extreme sun sensitivity. The lecture also introduces the concept of synthetic lethality and how it underlies the success of PARP inhibitors in BRCA-mutant cancers.
- Hereditary Cancer Syndromes: BRCA, Lynch, and Li-Fraumeni9:58Some families carry dramatically elevated cancer risk traceable to specific inherited mutations, and this lecture profiles the most important syndromes. Hereditary breast and ovarian cancer syndrome from BRCA1 or BRCA2 mutations produces lifetime breast cancer risks approaching seventy percent and substantial ovarian cancer risk, with management options including enhanced surveillance, chemoprevention, and risk-reducing surgery. Lynch syndrome from mismatch repair gene mutations predisposes to colorectal, endometrial, and several other cancers, with surveillance colonoscopy beginning in young adulthood. Li-Fraumeni syndrome from TP53 mutations produces extraordinary risk for diverse malignancies starting in childhood, including sarcomas, brain tumors, and breast cancer. You will learn how to recognize family histories suggestive of these syndromes and the principles guiding genetic testing and risk management.
- The Multi-Hit Model and Cancer Evolution10:35Cancer rarely results from a single mutation, and this lecture explains the stepwise accumulation of genetic changes that drives malignant transformation. You will learn how the multi-hit model, first formalized by Knudson and Vogelstein, describes how cells acquire successive mutations in oncogenes, tumor suppressors, and DNA repair genes over years or decades. The classic adenoma-to-carcinoma sequence in colorectal cancer illustrates this beautifully, with mutations in APC, KRAS, SMAD4, and TP53 accumulating as a benign polyp progresses to invasive cancer. The lecture also introduces clonal evolution, where genetically diverse subclones within a tumor compete and respond differently to therapy, and explains why this heterogeneity underlies treatment resistance and the push toward combination and adaptive therapies.
- Section 5 Quiz: Epigenetics and Cancer Genetics
- Roleplay: Epigenetics and Cancer Genetics
- Pharmacogenomics: When Genes Shape Drug Response10:01Genetic variation profoundly influences how patients metabolize and respond to medications, and this lecture explores the principles of pharmacogenomics. You will learn how variants in cytochrome P450 enzymes, particularly CYP2D6 and CYP2C19, classify patients as poor, intermediate, extensive, or ultrarapid metabolizers, with major implications for drugs like codeine, clopidogrel, and many antidepressants. The lecture covers high-stakes examples including HLA-B*57:01 testing before abacavir to prevent hypersensitivity, TPMT testing before thiopurine therapy to prevent myelosuppression, and DPYD testing before fluoropyrimidine chemotherapy. You will also see how warfarin dosing was an early pharmacogenomic success story and how the field is now embedded in clinical guidelines that turn genetic data into actionable prescribing decisions.
- Principles of Genetic Counseling7:38Communicating genetic information to patients and families requires specific skills and ethical frameworks, and this lecture introduces the core principles of genetic counseling. You will learn the non-directive philosophy that distinguishes genetic counseling from much of clinical medicine, where counselors help patients understand options and make their own decisions rather than recommending a course of action. The lecture covers pedigree construction and analysis, risk communication using clear language and visual aids, and the psychological dimensions of receiving genetic information including survivor guilt, decisional regret, and the ripple effects on extended family members. You will also explore ethical issues around consent for genetic testing, the right not to know, duty to warn at-risk relatives, and the special considerations for testing children for adult-onset conditions.
- Prenatal Genetic Screening and Diagnosis11:58Genetic information now plays a major role in prenatal care, and this lecture surveys the modern screening landscape. You will learn how first-trimester combined screening uses maternal serum markers and nuchal translucency to estimate risk for common aneuploidies, how cell-free fetal DNA in maternal blood has revolutionized non-invasive screening with dramatically higher sensitivity, and how diagnostic procedures like chorionic villus sampling and amniocentesis remain the gold standard for definitive testing. The lecture addresses expanded carrier screening that identifies couples at risk for recessive disorders before pregnancy, the role of preimplantation genetic testing during in vitro fertilization, and the ethical complexity surrounding selective termination and the implications of genetic information for reproductive decisions.
- Newborn Screening: Catching Disease Before Symptoms12:12Newborn screening represents one of public health's greatest successes, and this lecture explains how it works and why it matters. You will learn how every newborn in most developed countries is screened for a panel of treatable genetic and metabolic conditions using a few drops of blood from a heel prick, and how this brief test prevents lifelong disability and death in thousands of children each year. The lecture covers classic conditions like phenylketonuria, congenital hypothyroidism, and galactosemia, then explores the expansion of panels to include cystic fibrosis, sickle cell disease, severe combined immunodeficiency, and spinal muscular atrophy. You will also examine the criteria used to add conditions to screening panels and the ongoing debates about appropriate scope, parental consent, and storage of residual specimens.
- The Future of Genetic Medicine11:06Genetic medicine is advancing rapidly, and this closing lecture surveys the frontier and what it means for patients and clinicians. You will learn how gene therapy has finally delivered on decades of promise with approved treatments for spinal muscular atrophy, sickle cell disease, certain inherited blindnesses, and hemophilia, and how CRISPR-based editing is moving from laboratory to clinic. The lecture explores RNA-based therapeutics including antisense oligonucleotides and small interfering RNAs that have transformed treatment of conditions like Duchenne muscular dystrophy and transthyretin amyloidosis. You will also consider the ethical, social, and equity challenges that accompany these advances, including the staggering cost of gene therapies, questions about germline editing, and the imperative to ensure that genetic medicine serves diverse populations rather than widening existing disparities.
- Section 6 Quiz: Applied Genetics in Clinical Practice
- Roleplay: Applied Genetics in Clinical Practice
Requirements
- Basic familiarity with DNA, RNA, and protein synthesis at the level of introductory biology
- General understanding of cellular structure and function
- Working knowledge of human anatomy and physiology terminology
- Comfort with biomedical vocabulary, though clinical terms are explained as introduced
- No prior genetics coursework required beyond high school biology
Description
This course contains the use of artificial intelligence.
Every disease has a story written in DNA, and learning to read that story has become one of the most powerful skills in modern medicine. Pathological genetics sits at the heart of contemporary clinical practice, from explaining why one infant is born with cystic fibrosis while another inherits sickle cell disease, to predicting which patients will respond to chemotherapy and which require alternative regimens. Whether you are entering medicine, advancing through pathology training, studying genetic counseling, or simply trying to understand the molecular foundations of the diseases you encounter, this course gives you the conceptual framework to think clearly about how genetic changes produce human illness.
You will begin with the fundamentals of mutation, learning to distinguish point mutations, insertions, deletions, trinucleotide expansions, and chromosomal rearrangements, and to predict how each type affects protein structure and function. From there you will master the four classical Mendelian inheritance patterns through landmark diseases including Huntington disease, Marfan syndrome, cystic fibrosis, sickle cell disease, Duchenne muscular dystrophy, and the mitochondrial encephalopathies. You will then tackle chromosomal disorders ranging from Down syndrome to subtle microdeletion syndromes, complex multifactorial inheritance behind diabetes and cardiovascular disease, and the epigenetic mechanisms underlying imprinting disorders and cancer.
The course is designed for medical students, pathology residents, genetics and genetic counseling students, nursing and pharmacy learners, and any healthcare professional who needs solid conceptual grounding in genetic disease mechanisms. You should arrive with basic familiarity with DNA, RNA, and protein synthesis, and a general sense of human anatomy and physiology. By the end you will recognize inheritance patterns from pedigrees, predict molecular consequences of specific mutations, understand the genetic architecture of common diseases, apply pharmacogenomic principles, and engage thoughtfully with genetic counseling and screening programs.
What makes this course different is its focus on conceptual mastery rather than memorization, with every abstract principle anchored to concrete clinical examples and explained through clear visual frameworks. Enroll today and gain the genetic literacy that increasingly defines excellent twenty-first century medical practice.
Who this course is for:
- Medical students preparing for preclinical exams or clinical rotations involving genetic disease
- Pathology and clinical genetics residents seeking structured conceptual review
- Genetic counseling students building foundational knowledge of disease mechanisms
- Nursing, pharmacy, and allied health professionals encountering genetic conditions in practice
- Science students and healthcare professionals curious about how mutations translate into human disease