Research Article
Volume 9 Issue 6 - 2020
Steroid Metabolic Consequences of 7-Dehydrosterol Reductase Deficiency (SLO)
Fred Chasalow1,2*, Sandra Blethen3
1Managing Partner, IOMA LLC, USA
2Visiting Professor, Department of Laboratory Medicine, VAMC, San Francisco, CA, USA
3Consultant, USA
*Corresponding Author: Fred Chasalow, Visiting Professor, Department of Laboratory Medicine, VAMC, San Francisco, CA, USA.
Received: April 27, 2020; Published: May 18, 2020


Background: Individuals affected with Smith-Lemli-Opitz (SLO) syndrome have 7-dehydro-sterol reductase deficiency. This enzyme catalyzes the last step in cholesterol biosynthesis. Earlier, we showed that infants with SLO failed to produce polar steroids during the immediate neonatal period. In 2018, we reported the isolation and characterization of the four major polar steroids, which are phosphocholine esters. One of the four steroids has 21 carbon atoms. The other three have 23 carbon atoms. The phosphocholine steroids are spiral steroids. Their structure is similar to spironolactone and they may also function as potassium sparing diuretics. Now that we know the identity of each steroid, we have reexamined serum from patients with SLO.

Methods: For this study, the phosphocholine steroid concentration in 12 serum samples: six from affected individuals and six from obligate heterozygotes were determined by mass spectroscopy. We anticipated that the serum from affected individuals would have high levels of the precursors and low levels of the active compound and its metabolites.

Results: The actual observations did not fit the expected pattern. All 12 samples had low levels of the four phosphocholine steroids that we had previously detected in cord serum obtained from normal infants. There was no difference between males and females. The serum samples from the obligate heterozygotes had a novel, extra steroid phosphoester which we designated as C369.

Conclusion: We propose that, after the neonatal period, the diet is rich in potassium and there is no continuing need for a potassium retaining hormone, similar to spironolactone. However, in times of biochemical stress, there might be a basis for replacement hormone therapy. In view of the severe consequences to the affected individuals during pregnancy and the neonatal period, we propose that C369 may provide a compensating selective advantage to account for the persistence of these mutations in the world genome.

Keywords: SLO; DLM; Ionotropin; Potassium Sparing Diuretics; 7-Dehydrosterol Reductase


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Citation: Fred Chasalow and Sandra Blethen. “Steroid Metabolic Consequences of 7-Dehydrosterol Reductase Deficiency (SLO)”. EC Paediatrics 9.6 (2020): 60-69.

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