Abstract
Background: We encountered 7 Japanese patients with bile acid synthesis disorders (BASD) over 21 years between 1996 and 2017. Diagnoses were made by bile acid and genetic analyses. We gave low-dose, long-term chenodeoxycholic acid (CDCA) treatment to 5 of the patients, who had 3β-hydroxy-Δ 5 -C 27 -steroid dehydrogenase/isomerase (3β-HSD) deficiency (n=3) or Δ 4 -3-oxosteroid 5β-reductase (5β-reductase) deficiency (n=2). Another patient with the latter diagnosis whose bile acid analyses had mitigating features was maintained on ursodeoxycholic acid according to parental preferences and now remains healthy after discontinuation of treatment. A patient with oxysterol 7α-hydroxylase deficiency developed liver failure and fully recovered after successful liver transplantation. We used clinical records to clarify long-term outcome and value of CDCA in the other patients. Efficacy of CDCA treatment was evaluated in the 5 patients given a low dose (5 to 10 mg/kg/day) for a long term. Results: Medians with ranges of current patient ages and duration of CDCA treatment are10 years (8 to 43) and 10 years (8 to 21), respectively. All 7 patients, who had homozygous or compound heterozygous mutations in the HSD3B7 , SRD5B1 , or CYP7B1 gene, are currently in good health without liver dysfunction. In the 5 patients with CDCA treatment, hepatic function gradually improved following initiation. No adverse effects were noted. Conclusions: We concluded that low-dose CDCA treatment is effective in 3β-HSD deficiency and 5β-reductase deficiency, as cholic acid has been in other countries. BASD carry a good prognosis following early diagnosis and initiation of long-term, low-dose CDCA treatment.