Source / episode info

• **Episode:**455
• **Title:**Divine Intervention Episode 455: The HY Autosomal Dominant Disorders Podcast (for Step 1-3)
• **Published:**2023-04-27
• Source:Episode page

One-liner

This episode reviews high-yield autosomal dominant disorders, focusing on the clinical presentation of Huntington's disease (HD), the genetics and physical findings of Autosomal Dominant Polycystic Kidney Disease (ADPKD), and the constellation of symptoms seen in hereditary cancer syndromes.

High-yield summary

• Huntington's Disease (HD): An autosomal dominant neurodegenerative disorder caused by a trinucleotide repeat expansion ({CAG}) in the HTT gene on chromosome 4. Clinical triad includes chorea, cognitive decline/dementia, and psychiatric symptoms (e.g., irritability).
• Autosomal Dominant Polycystic Kidney Disease (ADPKD): Characterized by progressive cystic kidney enlargement. The most common mutation is in {PKD1} (chromosome 16); a less common one is in {PKD2} (chromosome 4). Physical exam may reveal an apical murmur due to enlarged kidneys.
• Hereditary Cancer Syndromes: A constellation of multiple, varied primary cancers (e.g., breast, colon, brain) with a strong family history suggests a genetic predisposition (e.g., Lynch Syndrome or other tumor suppressor gene mutations).
• Genetic Counseling: When diagnosing an autosomal dominant disorder, genetic testing and counseling are critical for risk assessment in at-risk family members.

Learning objectives

• Describe the clinical presentation of Huntington's disease, including its characteristic triad.
• Differentiate between \text{PKD1} and \text{PKD2} mutations in Autosomal Dominant Polycystic Kidney Disease (ADPKD).
• Recognize the constellation of symptoms suggestive of a hereditary cancer syndrome versus sporadic malignancy.
• Understand the importance of genetic counseling when diagnosing an autosomal dominant disorder.
• Correlate physical exam findings (e.g., apical murmur) with underlying systemic disease processes (e.g., PKD).

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