For instance, hypomorphic mutations of the catalytic subunit of Polε, POLE, have been described in patients affected by FILS (facial dysmorphism, immunodeficiency, livedo, short stature) syndrome and IMAGe (intrauterine growth restriction, metaphyseal dysplasia, adrenal hypoplasia congenita, and genital anomalies in males) syndrome in association with variable degrees of immunodeficiency (Pachlopnik Schmid et al., 2012; Logan et al., 2018). Here, POLE is linked to alternating hemiplegia of childhood.