Dried blood spot-based newborn screening for bile acid synthesis disorders, Zellweger spectrum disorder, and Niemann-Pick type C1 by detection of bile acid metabolites

Efficacy and safety of switching therapy from chenodeoxycholic acid to cholic acid in Japanese patients with bile acid synthesis disorders

Objectives

This study aimed to assess the safety and efficacy of cholic acid (CA) treatment over 74 weeks in Japanese patients with inherited enzymatic bile acid synthesis disorders (BASD).

Methods

This phase 3, open-label, single-arm study enrolled four Japanese patients diagnosed with BASD, including two with 3β-hydroxy-Δ 5-C27-steroid dehydrogenase/isomerase (HSD3B7) deficiency and two with Δ 4-3-oxosteroid 5β-reductase (SRD5B1) deficiency. The patients had received chenodeoxycholic acid (CDCA) treatment but were switched to CA treatment. Treatment efficacy was evaluated by measuring serum and urinary bile acid levels and liver-related biomarkers, and adverse events were evaluated to monitor safety.

Results

The daily CA doses ranged from 3.8 to 13.7 mg/kg/day. Laboratory values of liver-related biomarkers were maintained within normal ranges or improved. Bile acid analysis revealed CDCA replacement with CA in serum within the initial few weeks of CA treatment. Urinary concentrations of toxic bile acid metabolites associated with liver damage were higher than serum. Adverse effects from CA treatment were mild to moderate, and no treatment discontinuations were due to adverse events.

Conclusions

CA treatment over 74 weeks resulted in favorable efficacy and safety outcomes in Japanese patients with BASD, consistent with previous studies. These results support the utility of CA as a therapeutic option for Japanese patients with BASD.

Current Status of Newborn Bloodspot Screening Worldwide 2024: A Comprehensive Review of Recent Activities (2020-2023)

Newborn bloodspot screening (NBS) began in the early 1960s based on the work of Dr. Robert "Bob" Guthrie in Buffalo, NY, USA. His development of a screening test for phenylketonuria on blood absorbed onto a special filter paper and transported to a remote testing laboratory began it all. Expansion of NBS to large numbers of asymptomatic congenital conditions flourishes in many settings while it has not yet been realized in others. The need for NBS as an efficient and effective public health prevention strategy that contributes to lowered morbidity and mortality wherever it is sustained is well known in the medical field but not necessarily by political policy makers. Acknowledging the value of national NBS reports published in 2007, the authors collaborated to create a worldwide NBS update in 2015. In a continuing attempt to review the progress of NBS globally, and to move towards a more harmonized and equitable screening system, we have updated our 2015 report with information available at the beginning of 2024. Reports on sub-Saharan Africa and the Caribbean, missing in 2015, have been included. Tables popular in the previous report have been updated with an eye towards harmonized comparisons. To emphasize areas needing attention globally, we have used regional tables containing similar listings of conditions screened, numbers of screening laboratories, and time at which specimen collection is recommended. Discussions are limited to bloodspot screening.

Navigating cholestasis: identifying inborn errors of bile acid metabolism for precision diagnosis

Inborn errors of bile acid metabolism (IEBAM) cause cholestasis during the neonatal period, and 8 types of IEBAM have been reported to date. IEBAM accounts for approximately 2% of cases of cholestasis of unknown cause. As only 10 patients have been identified in Japan, IEBAM presents diagnostic challenges due to the similarity of clinical symptoms with biliary atresia, thus necessitating precise differentiation to avoid unnecessary invasive procedures. Laboratory tests in IEBAM are characterized by normal γ-glutamyltransferase (GGT) and serum total bile acid (STBA) levels despite the presence of cholestasis; therefore, measuring STBA and GGT is essential to distinguishing biliary atresia from IEBAM. With suspected IEBAM, liquid chromatography-mass spectrometry (LC/MS) analysis of urinary bile acids is needed to optimize diagnostic and therapeutic efficacy and avoid open cholangiography and initiate treatment for primary bile acids such as cholic acid or chenodeoxycholic acid. This prospective report aims to increase awareness of IEBAM by highlighting the characteristics of general blood test and bile acid profiles from LC/MS analyses of blood, urine, and stool samples.