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Smith–Lemli–Opitz syndrome

From WikiMD's Wellness Encyclopedia

(Redirected from 7-Dehydrocholesterol reductase deficiency)
Smith-Lemli-Opitz Syndrome 1

Smith–Lemli–Opitz syndrome (SLOS) is a rare autosomal recessive genetic disorder characterized by multiple congenital anomalies and intellectual disability. It is caused by mutations in the DHCR7 gene, which encodes the enzyme 7-dehydrocholesterol reductase. This enzyme is crucial for the final step in the cholesterol biosynthesis pathway.

Signs and Symptoms[edit | edit source]

Individuals with Smith–Lemli–Opitz syndrome exhibit a wide range of symptoms, which can vary in severity. Common features include:

Genetics[edit | edit source]

Smith–Lemli–Opitz syndrome is inherited in an autosomal recessive manner. This means that an affected individual must inherit two copies of the mutated DHCR7 gene, one from each parent. Carriers of a single mutated gene typically do not show symptoms of the disorder.

Pathophysiology[edit | edit source]

The DHCR7 gene mutation leads to a deficiency in the enzyme 7-dehydrocholesterol reductase, which is responsible for converting 7-dehydrocholesterol to cholesterol. As a result, individuals with SLOS have low levels of cholesterol and elevated levels of 7-dehydrocholesterol. Cholesterol is essential for normal embryonic development, cell membrane structure, and the synthesis of steroid hormones and bile acids.

Diagnosis[edit | edit source]

Diagnosis of Smith–Lemli–Opitz syndrome is based on clinical features and confirmed by biochemical testing showing elevated levels of 7-dehydrocholesterol in the blood. Genetic testing can identify mutations in the DHCR7 gene.

Treatment[edit | edit source]

There is no cure for Smith–Lemli–Opitz syndrome, and treatment is symptomatic and supportive. Management may include:

  • Dietary supplementation with cholesterol
  • Physical therapy and occupational therapy to address developmental delays and hypotonia
  • Surgical interventions for congenital anomalies such as cleft palate or genital abnormalities
  • Behavioral therapy and educational support for intellectual disability and behavioral issues

Prognosis[edit | edit source]

The prognosis for individuals with Smith–Lemli–Opitz syndrome varies depending on the severity of the condition. Early intervention and supportive care can improve the quality of life for affected individuals.

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