DNAJC21‐related thrombocytopenia in a young adult female

Bone marrow failure type 3 (BMFS3) (MIM:617052) is a subtype of inherited bone marrow failure syndromes (IBMFS) caused by homozygous pathogenic variants in DNAJC21. It was first defined in 2016, and to date, 19 patients have been reported. Here we report the first adult patient; a 20-year-old female with a novel frameshift variant in DNAJC21 presents with thrombocytopenia, dysmorphic findings, and ovarian agenesis. Our patient expands the clinical spectrum to the milder end and suggests that DNAJC21-related disorders can have relatively mild presentations. Investigation of DNAJC21 variants in both childhood and adult patients with persistent, non-progressive thrombocytopenia will allow to broaden the gene-related phenotypic and genotypic spectrum and elucidate the pathophysiology. Therefore, we encourage revisiting undiagnosed patients to offer whole exome sequencing (WES) in adulthood.