Two neonatal cholestasis patients with mutations in the SRD5B1 (AKR1D1) gene: Diagnosis and bile acid profiles during chenodeoxycholic acid treatment

Background and aims: In two Japanese infants with neonatal cholestasis, 3-oxo-Δ⁴-steroid 5β-reductase deficiency was diagnosed based on mutations of the SRD5B1 gene. Unusual bile acids such as elevated 3-oxo-Δ⁴ bile acids were detected in their serum and urine by gas chromatography-mass spectrometry. We studied effects of oral chenodeoxycholic acid treatment. Patients and methods: SRD5B1 gene analysis used peripheral lymphocyte genomic DNA. Diagnosis and treatment of these two patients were investigated retrospectively and prospectively investigated. Results: With respect to SRD5B1, one patient was heterozygous (R266Q, a novel mutation) while the other was a compound heterozygote (G223E/R261C). Chenodeoxycholic acid treatment was effective in improving liver function and decreasing unusual bile acids such as 7α-hydroxy- and 7α,12α- dihydroxy-3-oxo-4-cholen-24-oic acids in serum and urine. Conclusion: Primary bile acid treatment using chenodeoxycholic acid was effective for these patients treated in early infancy before the late stage of chronic cholestatic liver dysfunction.