CEP41 Mutations Alter Cortical Neuron Ratios in Human Organoid Models

The clinical heterogeneity of autism spectrum disorder is mirrored by a complex genetic landscape involving more than 100 risk genes that influence early brain assembly [1, 2]. Transcriptomic analyses of human induced pluripotent stem cells (adult cells reprogrammed to an embryonic-like state) indicate that diverse genetic insults often converge on shared pathways governing the proliferation of neural progenitors and the maturation of synaptic circuits [3, 1]. For instance, mutations in the amino acid transporter SLC7A5 disrupt the balance of large neutral amino acids, which are essential nutrients for protein synthesis, leading to altered lipid metabolism and stage-specific shifts in neuronal activity patterns [4]. Similarly, homozygous mutations in the CNTNAP2 gene have been shown to drive increased neural progenitor proliferation and significant brain overgrowth in forebrain organoid models [5]. While primary cilia (sensory organelles on the cell surface) are known regulators of signaling, a recent study investigating the CEP41 R242H mutation demonstrates how shortened cilia and reduced tubulin polyglutamylation (a post-translational modification affecting microtubule stability) impair the differentiation of both excitatory and inhibitory neurons [6]. These cellular imbalances likely contribute to the excitation and inhibition dysregulation frequently observed in clinical autism presentations [6, 7].