Genes encoding HS-modifying enzymes include NDST3 implicated in schizophrenia by a genome-wide association study supported by expression profiling, NDST1 in which a compound heterozygous mutation was found in developmental delay, and HS3ST5 associated with autism (Armstrong et al., 2017, Lencz et al., 2013, Wang et al., 2009). Here, HS3ST5 is linked to autism.