Background: This study reports our experience over the last
six years in the diagnosis of Smith-Lemli-Opitz syndrome
and other inborn errors of cholesterol biosynthesis.
Methods: Gas chromatography/mass spectrometry was used
to obtain sterol profiles in plasma and erythrocyte membranes
of suspected patients.
Results: Plasma sterol reference values calculated in unaffected
subjects (ns276) were in agreement with those previously
reported. Among patients investigated from 2005 to
2010, we report 16 patients affected by Smith-Lemli-Opitz
syndrome, three of whom represent new cases and 13 of
whom were follow-up patients. In this period we also identified
a new case of chondrodysplasia punctata 2 X-linked.
The estimated incidence obtained for Smith-Lemli-Opitz
syndrome was 1:93 suspected patients (1.08%). We also
studied the effect of storage on the dehydrocholesterols/
cholesterol ratio in plasma and erythrocyte membranes of
patients affected by Smith-Lemli-Opitz syndrome stored at
–208C for up to 22 and 20 months, respectively. A significant
negative linear correlation between storage time and the
dehydrocholesterols/cholesterol ratio was identified in both
plasma and erythrocyte membranes. The decrease in the
dehydrocholesterols/cholesterol ratio in erythrocyte membranes
was at least two-fold higher than in plasma.
Conclusions: The results of this study may be helpful for
diagnosis and interpretation of data in patients with findings
suggestive of a cholesterol biosynthesis defect
