LAUSR

Abstract Background and aims Low phospholipid-associated cholelithiasis syndrome (LPAC) is characterized by recurrent symptomatic cholelithiasis in young adults associated with ABCB4 gene mutations. Current diagnosing criteria are complex and heterogeneous, making this a largely underdiagnosed entity. Also, although recommended, genetic testing is not necessary for the diagnosis and its real advantages are not clear. The aim of our study was to explore the prevalence of ABCB4 mutations in symptomatic patients with cholelithiasis before the age of 30. Methods We conducted a multicentric prospective cohort study including patients with symptomatic cholelithiasis presenting before 30 years of age in 4 Portuguese centres between January 2017 and December 2019. ABCB4 gene was analyzed by next generation sequencing (NGS) including all exons and flanking regions. In 17/32 patients ABCB11 and ATP8B1 variants were also analyzed by NGS. Results Thirty-two patients were included (75% females, median age of symptom onset was 23 ± 5 years). We found that 8/32 (25%) patients had mutations in ABCB4 gene, 3/17 (18%) in ATP8B1 gene and 1/17 (6%) in ABCB11 gene. 44% (8/18) of patients with LPAC syndrome criteria had identified variants, while the prevalence of mutations in patients with symptoms onset before 30 as sole criteria was 29%. Conclusion Our results suggest that LPAC should be systematically suspected and investigated in patients with symptomatic cholelithiasis before age of thirty, but genetic testing should only be attempted in patients complying with the more stringent LPAC criteria.