FBRSL1 and autism spectrum disorder due to AUTS2 deficiency: Interestingly, while the severe AUTS2 syndrome phenotype was caused by variants of the C-terminus (Beunders et al., 2013), the situation was different for the three patients with the FBRSL1-associated syndromic phenotype: all three patients harbor a truncating variant (stop mutation in two patients and a frameshift variant with premature stop codon in the other patient) in the N-terminus of FBRSL1 affecting the short N-terminal isoforms (Ufartes et al., 2020).