U01.01.060 Williams syndrome

Williams syndrome is a rare genetic disorder caused by a congenital microdeletion of the long arm of chromosome 7. This microdeletion includes the elastin gene, leading to various distinctive features.

Key Findings of Williams Syndrome

Distinctive “Elfin” Facies: A characteristic facial appearance with a broad forehead, short nose, wide mouth, and full cheeks.
Intellectual Disability: Mild to moderate cognitive impairment is common.
Hypercalcemia: Elevated calcium levels can lead to kidney stones or other complications.
Verbal Skills: Individuals often have well-developed verbal abilities despite intellectual challenges.
Extreme Friendliness with Strangers: A hallmark behavior where individuals are unusually friendly and trusting of people they do not know.
Cardiovascular Problems:
- Supravalvular Aortic Stenosis: A narrowing of the aorta above the valve, leading to hypertension or heart failure.
- Renal Artery Stenosis: Narrowing of the arteries supplying blood to the kidneys, potentially leading to hypertension.

Clinical Associations and Mnemonic

Mnemonic: Think of Will Ferrell in the movie Elf to remember the combination of “elfin” facies, friendly demeanor, and cardiovascular issues (like aortic stenosis).

Table: Key Features of Williams Syndrome

Feature	Description
Genetic Cause	Congenital microdeletion of long arm of chromosome 7
Elastin Gene	The affected gene responsible for cardiovascular issues
Facial Characteristics	“Elfin” facies, broad forehead, short nose, full cheeks
Cognitive Abilities	Intellectual disability (mild to moderate)
Verbal Skills	Well-developed despite cognitive delays
Behavior	Extremely friendly, social, and trusting
Cardiovascular Issues	Supravalvular aortic stenosis, renal artery stenosis
Metabolic Issues	Hypercalcemia

Points to Remember for USMLE Step 1:

Key Genetic Cause: Microdeletion on chromosome 7, which includes the elastin gene.
Cardiovascular Manifestations: Supravalvular aortic stenosis and renal artery stenosis are critical to recognize in this condition.
Distinctive Behavioral Traits: Extreme friendliness, verbal proficiency despite cognitive challenges, and “elfin” facies.
Mnemonic: “Think Will Ferrell in Elf” for facial features and friendly behavior.

USMLE Step 1 Review Series

Curriculum

U01.01.060 Williams syndrome

Key Findings of Williams Syndrome

Clinical Associations and Mnemonic

Table: Key Features of Williams Syndrome

Points to Remember for USMLE Step 1:

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