[Smith-Lemli-Opitz syndrome].

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.