ARID1A and Hydrocephalus: Shared abnormalities were growth delay, which has been observed especially in SMARCB1 pathogenic variants (Santen et al. 2013), and hydrocephalus, which has only recently been described as a common prenatal characteristic in ARID1A pathogenic variants (but not in SMARCB1 variants) (van der Sluijs et al. 2022).