In conclusion, two patients both presented with ID, microcephaly, and MICPCH, with mild clinical differences (with or without special facial abnormality), which expands the spectrum of genotype and phenotype correlations of CASK‐linked disorders in Han Chinese, providing new insights into the molecular mechanism of CASK‐linked disorders and helping to further explore the contribution of other protein–protein interactions. The gene discussed is CASK; the disease is microcephaly.