Changes in the RMRP gene result in rare skeletal disorders: metaphyseal dysplasia without hypotrichosis (MDWH) and cartilage-hair hypoplasia (CHH). We hypothesized that MDWH may, similar to CHH, associate with immune deficiency and cancer. We collected data for 80 patients with RMRP mutations followed for over 30 years, and among them we identified 10 patients with features consistent with MDWH during pre-school age. Eight of these patients developed cancer or significant immunodeficiency during follow-up. We concluded that MDWH can present with severe late-onset immunodeficiency features in addition to skeletal changes and thus should be re-classified and managed as CHH. (By Dr Svetlana Vakkilainen, https://jmg.bmj.com/content/early/2019/08/14/jmedgenet-2019-106131 )