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[Smith-Lemli-Opitz syndrome]
Insights
Smith-Lemli-Opitz syndrome (SLOS) is a metabolic disorder affecting cholesterol biosynthesis. This case highlights a severe, lethal presentation (Type II SLOS) despite normal cholesterol levels due to nutritional support.
Area of Science:
- Biochemistry
- Genetics
- Pediatrics
Background:
- Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive metabolic disorder.
- It involves a defect in cholesterol biosynthesis, leading to elevated 7-dehydrocholesterol (7-DHC).
- SLOS is classified into Type I (classic) and Type II (severe).
Observation:
- A full-term female infant presented with severe hypotonia, absent reflexes, and abnormal crying.
- Multiple congenital anomalies were noted, including facial dysmorphia and limb abnormalities.
- Elevated 7-DHC and 8-DHC levels were observed despite normal blood cholesterol.
Findings:
- The infant experienced a severe neurological deficit and died on day 16.
- Enteral and parenteral nutrition were required due to major alimentary tract defects.
- The clinical severity and lethal outcome supported classification as Type II SLOS.
Implications:
- This case underscores the diagnostic challenges in SLOS, especially with nutritional interventions masking hypercholesterolemia.
- Early identification and management of SLOS are crucial for affected infants.
- Understanding the genotype-phenotype correlation in SLOS is vital for prognosis.
Background:
Smith-Lemli-Opitz syndrome (SLOS) is an autosomic recessive metabolic affection. Children affected by SLOS exhibit a defect in cholesterol biosynthesis associated with a high concentration of cholesterol precursor 7 dehydrocholesterol (7 DHC) and its isomers, which is due to an enzymatic block at the level of delta-7-DHC reductase. SLOS has been subdivided into two types on the basis of clinical severity: type I is the classic and type II is the severe one.
Case Report:
A full term female was born from a pregnancy complicated by oligoamniosis and intra-uterine growth retardation. The neurologic status was immediately impaired with severe hypotonia, absence of reflexes, and abnormal crying. She exhibited multiple congenital anomalies with a facial dysmorphia, anomalies of members, unicornus uterus and a pyloric stenosis. Plasmatic concentration exhibited a normal cholesterolemia contrasting with an elevated level of 7 and 8 DHC. Major alimentary tract defect led to enteral and parenteral nutrition. The severe neurological defect led to death on the 16th day of life.
Conclusion:
Despite normal blood cholesterol levels that can be attributed to enteral and parenteral nutrition, the severity of clinical findings and the lethal course permit to classify this case as type II.