Identification of Rare, Single-Nucleotide Mutations in NDE1 and Their Contributions to Schizophrenia Susceptibility.

Nuclear distribution E homolog 1 (NDE1), located within chromosome 16p13.11, plays an essential role in microtubule organization, mitosis, and neuronal migration and has been suggested by several studies of rare copy number variants to be a promising schizophrenia (SCZ) candidate gene. Recently, increasing attention has been paid to rare single-nucleotide variants (SNVs) discovered by deep sequencing of candidate genes, because such SNVs may have large effect sizes and their functional analysis may clarify etiopathology. We conducted mutation screening of NDE1 coding exons using 433 SCZ and 145 pervasive developmental disorders samples in order to identify rare single nucleotide variants with a minor allele frequency ≤5%. We then performed genetic association analysis using a large number of unrelated individuals (3554 SCZ, 1041 bipolar disorder [BD], and 4746 controls). Among the discovered novel rare variants, we detected significant associations between SCZ and S214F (P = .039), and between BD and R234C (P = .032). Furthermore, functional assays showed that S214F affected axonal outgrowth and the interaction between NDE1 and YWHAE (14-3-3 epsilon; a neurodevelopmental regulator). This study strengthens the evidence for association between rare variants within NDE1 and SCZ, and may shed light into the molecular mechanisms underlying this severe psychiatric disorder.