RESUMO
Liver diseases remain unexplained in up to 30% of adult patients; genetic analysis could help establish the correct diagnosis. In six adult patients with cryptogenic liver disease, we performed whole-exome sequencing (WES) and evaluated the individual predisposition to progressive fatty liver disease by polygenic risk scores (PRS). In one patient, WES was allowed to diagnose the Hermansky-Pudlak syndrome. In the other two patients, genetic variants in LDLRAP1/MSH6 and ALDOB genes were identified, contributing to explaining the clinical presentation and disease pathogenesis (50% diagnostic uptake). In the other three patients, rare variants with a high likelihood of disrupting protein function in APOB, ATP7B, ABCB4 and ATP8B1 were identified. One patient who developed hepatocellular carcinoma during the follow-up had a high PRS value. The study supports the role of WES, combined with risk stratification by PRS and accurate clinical assessment in improving the diagnosis and informed management in patients with cryptogenic liver disease, a positive family history or severe fatty liver not fully accounted for by environmental triggers.
Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Adulto , Carcinoma Hepatocelular/genética , Exoma/genética , Humanos , Neoplasias Hepáticas/genética , Mutação , Sequenciamento do ExomaRESUMO
Fatty liver disease (FLD) is a growing health issue with burdening unmet clinical needs. FLD has a genetic component but, despite the common variants already identified, there is still a missing heritability component. Using a candidate gene approach, we identify a locus (rs71519934) at the Pleckstrin and Sec7 domain-containing 3 (PSD3) gene resulting in a leucine to threonine substitution at position 186 of the protein (L186T) that reduces susceptibility to the entire spectrum of FLD in individuals at risk. PSD3 downregulation by short interfering RNA reduces intracellular lipid content in primary human hepatocytes cultured in two and three dimensions, and in human and rodent hepatoma cells. Consistent with this, Psd3 downregulation by antisense oligonucleotides in vivo protects against FLD in mice fed a non-alcoholic steatohepatitis-inducing diet. Thus, translating these results to humans, PSD3 downregulation might be a future therapeutic option for treating FLD.