KATNAL2 encodes a protein similar to the A subunit of the p60 katanin protein and is widely expressed in the central nervous system.66 Katanin p60 acts to sever microtubules in the axons of neurons and is thought to play a role in neuronal migration, axonal growth and dendritic pruning.67-69 Thus, the KATNAL2 gene may play a role in neurodevelopment. Several other SNPs located in the nearby PIAS2, HDHD2 and IER3IP1 genes that are in relatively high LD (r-squared > 0.5) with the top SNP showed suggestive evidence for association (P < 1 × 10−5) (Figure 1b and Supplementary Table 6). The PIAS2 gene is involved in the regulation of transcription factors involved in the mitogen-activated protein kinase signaling pathway. Less is known about the biological function of the HDHD2 and IER3IP1 genes, but all three genes are moderately expressed in the brain.66
