Mutations in the cap subunit gene EXOSC3 and the core subunit gene EXOSC8 cause forms of pontocerebellar hypoplasia (PCH1b and PCH1c, respectively), neurological disorders characterized by atrophy of the pons and cerebellum (Wan et al. 2012; Biancheri et al. 2013; Boczonadi et al. 2014; Eggens et al. 2014; Schottmann et al. 2017; Morton et al. 2018), while mutations in the core subunit genes EXOSC5 and EXOSC9 have been linked to similar neurological defects including cerebellar degeneration, neuronopathy and neurodevelopmental delays (Burns et al. 2017, 2018; Slavotinek et al. 2020). The gene discussed is EXOSC3; the disease is pontocerebellar hypoplasia.