Gene expression analysis of WT vs Wdr47 deficient primary neurons

Corpus callosum (CC) is the largest interhemispheric connection that is largely formed by the axons of layer 2/3 callosal projection neurons (CPNs) through a series of tightly regulated cellular events.Defects in any of those steps may prevent the proper development of the corpus callosum resulting in a spectrum of disorders collectively referred to as corpus callosum dysgenesis (CCD). Here, we report 5 patients carrying bi-allelic variants in WDR47 presenting CCD together with microcephaly. Using a combination of in vitro and in vivo mouse models and complementation assays, we show that independently from its previously identified functions in neuronal migration and neurite extension, Wdr47 is required for survival of callosal neurons by contributing to the maintenance of mitochondrial and microtubule homeostasis. We further provide evidence that severity of the CCD phenotype is determined by the degree of the loss of function caused by the variants. Taken together, we identify WDR47 as a novel causative gene for corpus callosum abnormalities. To investigate how Wdr47 promotes neuronal survival, we established primary neuronal cultures from WT or Wdr47 deficient neurons. We then performed gene expression analysis at DIV6, 2 days before induction of neuronal death, using data obtained from RNA-seq of 4 samples per genotype coming from 3 independent cultures.