By contrast, non-truncating variants of SMARCB1, which are mostly located in the exons one, two, eight and nine, are associated with late-onset tumours, such as schwannoma and meningioma (Holsten et al. 2018), and with neurodevelopmental disorders, such as intellectual disability with plexus hyperplasia (Kleefstra et al. 2012; Diets et al. 2019) and the Coffin–Siris syndrome (Santen et al. 2013; Tsurusaki et al. 2014). This evidence concerns the gene SMARCB1 and neurodevelopmental disorder.