We also narrowed down the candidate genes to only one in AU1328302. An R125C mutation in CLTCL1, encoding clathrin heavy chain-like 1, was homozygous in both affected children, heterozygous in the parents and unaffected sibling, and predicted to be damaging (Table 2 and Figure S2). CLTCL1 is disrupted in a patient with features of DiGeorge syndrome, including intellectual disability, facial dysmorphia, long slender digits, and genital anomalies [28]. It encodes a member of the clathrin heavy chain family, representing a major structural component of coated pits and vesicles involved in intracellular trafficking, which are important to glutamate receptor turnover.
