gt;T variant in HPS4. All four patients presented with oculocutaneous albinism and a functional platelet defect. At the time of WES analysis, pulmonary fibrosis had developed in 3 of the 4 patients (75%), with a median age at onset of 50 years. None of the patients developed cytopenia, granulomatous colitis, chronic kidney failure, or cardiomyopathy. At our center, genetic diagnostics is a standard part of the evaluation of patients suspected of having inherited hematological disorders. Confirmation of an HPS diagnosis has a positive impact on individualized patient care, with early planning of lung transplantation being particularly important. Early detection of the disease is also significant for affected relatives.