Next-Generation Sequencing in Diagnosis of Monogenic Cholestatic Liver Disorders: A Single-Center Experience.

Abstract

Introduction: Cholestasis in childhood is a rare clinical condition, yet a definitive diagnosis is crucial for initiating treatment of these curable diseases and preventing related morbidity and mortality. The most common cause of infant cholestasis is biliary atresia (25-40%), followed by monogenic cholestatic diseases (25%), metabolic diseases (20%), and cryptogenic cholestasis. This study focuses on assessing the clinical utility of next-generation sequencing (NGS) panels, including clinical exome sequencing and whole exome sequencing, in diagnosing cholestatic diseases when the etiology cannot be elucidated through conventional methods.

Materials and methods: We conducted a retrospective examination of pediatric patients who sought care at a single-center pediatric gastroenterology department between August 2020 and March 2022 and were diagnosed with cholestasis. A total of 36 patients underwent a thorough investigation to rule out infectious, toxic, metabolic, structural, chromosomal, and endocrine causes. Patients whose diagnoses were established through traditional investigations were excluded from the study. The remaining 14 patients underwent either whole exome sequencing or targeted NGS methods.

Results: A definitive diagnosis was achieved for 12 patients, while 2 patients remained undiagnosed despite comprehensive genetic examinations. The most commonly encountered diseases in this cohort were progressive familial intrahepatic cholestasis, linked to mutations in the ABCB11, ATP8B1, and TJP2 genes, as well as Dubin-Johnson syndrome associated with ABCC2 mutations. NGS demonstrated a diagnostic accuracy of 85.7% in patients for whom a diagnosis could not be established through extensive traditional workup.

Conclusion: NGS emerges as a valuable diagnostic tool in cases of cholestasis where traditional methods fall short in providing a definitive diagnosis. Moreover, our study unveiled three previously undocumented variants in the ABCB11 [c.1165G>C; p.(Ala389Pro) and c.783 + 1G>A] and ABCC2 [c.4246_4247del; p.(Lys1416ValfsTer46)] genes.