Disorders of bile acid synthesis

Area of Science:

• Biochemistry
• Genetics
• Pediatric Hepatology

Background:

• Inborn errors of bile acid synthesis lead to severe cholestatic liver disease in infancy and progressive neurological disease later in life.
• Early diagnosis is critical as these conditions are often effectively treated with bile acid replacement therapy.
• Infantile cholestatic disease presents with conjugated hyperbilirubinemia, elevated transaminases, normal gamma-glutamyl transpeptidase, giant cell hepatitis, and fat-soluble vitamin malabsorption.

Purpose of the Study:

• To review inborn errors of bile acid synthesis.
• To highlight the importance of early diagnosis for effective treatment.
• To discuss diagnostic approaches, particularly urinary cholanoid analysis.

Main Methods:

• Review of literature on inborn errors of bile acid synthesis.
• Discussion of clinical presentations and diagnostic findings.
• Focus on electrospray ionization tandem mass spectrometry for urinary cholanoid analysis.

Main Results:

• Identified key clinical features of infantile cholestatic and childhood/adult neurological presentations.
• Highlighted urinary cholanoid analysis as a primary screening tool.
• Detailed specific enzyme deficiencies including 3β-hydroxysteroid-Δ5-C27-steroid dehydrogenase, Δ4-3-oxosteroid 5β-reductase, sterol 27-hydroxylase, oxysterol 7α-hydroxylase, and amidation defects (BAAT deficiency, bile acid-CoA ligase deficiency).

Conclusions:

• Inborn errors of bile acid synthesis require prompt diagnosis for timely intervention.
• Bile acid replacement therapy offers effective treatment for both cholestatic and neurological manifestations.
• Urinary cholanoid analysis using mass spectrometry is a vital diagnostic method for these rare genetic disorders.