CASK and microcephaly: Loss‐of‐function variants in the X‐chromosomal gene CASK, which encodes the calcium‐/calmodulin‐dependent serine protein kinase (CASK), are associated with a neurodevelopmental disorder termed microcephaly with pontocerebellar hypoplasia (MICPCH) in females (Najm et al. 2008; Valayannopoulos et al. 2012; Moog et al. 2013).