What is Smith-Lemli-Opitz Syndrome primarily characterized by?

What is Smith-Lemli-Opitz Syndrome primarily characterized by?

• A. A defect in chromosome 21
• B. A single gene disorder
• C. An increase in cholesterol
• D. An autosomal dominant inheritance

Answer: (B)

Smith-Lemli-Opitz Syndrome is primarily characterized by a single gene disorder. It is caused by mutations in the DHCR7 gene, which is crucial for the biosynthesis of cholesterol. This genetic defect leads to reduced levels of cholesterol and accumulation of its precursors, which is why individuals with this syndrome often have various developmental abnormalities, growth issues, and congenital malformations. The focus on a single gene emphasizes how a specific genetic mutation can lead to a wide range of symptoms, making it distinct from disorders that may involve multiple genetic or chromosomal abnormalities. Understanding that Smith-Lemli-Opitz Syndrome is a single gene disorder provides insight into its inheritance patterns, clinical features, and potential for genetic counseling.

Smith-Lemli-Opitz Syndrome is primarily characterized by a single gene disorder. It is caused by mutations in the DHCR7 gene, which is crucial for the biosynthesis of cholesterol. This genetic defect leads to reduced levels of cholesterol and accumulation of its precursors, which is why individuals with this syndrome often have various developmental abnormalities, growth issues, and congenital malformations.

The focus on a single gene emphasizes how a specific genetic mutation can lead to a wide range of symptoms, making it distinct from disorders that may involve multiple genetic or chromosomal abnormalities. Understanding that Smith-Lemli-Opitz Syndrome is a single gene disorder provides insight into its inheritance patterns, clinical features, and potential for genetic counseling.