Primary sclerosing cholangitis and overlap features of autoimmune hepatitis: A coming of age or an age-ist problem?

Autoimmune liver diseases are siloed into three syndromes that define clinical practice. These classifiers can, and are, challenged by variant presentations across all ages, something inevitable to disease definitions that rely on interpreting (inherently variable) semi-quantitative/qualitative clinical, laboratory, pathological or radiological findings. Furthermore this categorisation is premised on an ongoing absence of definable disease aetiologies. Clinicians thus encounter individuals with biochemical, serological, and histological manifestations that are common to both primary sclerosing cholangitis (PSC) and autoimmune hepatitis (AIH), often labelled as 'PSC/AIH-overlap'. In childhood the term 'autoimmune sclerosing cholangitis (ASC)' may be used, and some propose this to be a distinct disease process. In this article we champion the concept that ASC and PSC/AIH-overlap are not distinct entities. Rather, they represent inflammatory phases of PSC frequently manifesting earlier in the disease course, most notably in younger patients. Ultimately, disease outcomes remain similar to those of a more classical PSC phenotype observed in later life. Thus, we argue that it is now time to align disease names and descriptions used by clinicians across all patient subpopulations, to help unify care. This will enhance collaborative studies and ultimately contribute to rational treatment advances.