Cabezas syndrome (OMIM 300354) is a rare syndromic form of X-linked intellectual disability caused by de novo or inherited variants in the CUL4B gene. The gene is located on chromosome Xq24, contains 22 exons and encodes the protein cullin 4B, belonging to the cullin-RING ubiquitin ligase family which regulates the degradation of cellular proteins. The full-blown phenotype develops in males. CUL4B-heterozygotic females exhibit milder clinical features, yet the phenotype remains to be elucidated and may vary according to the mutation type and X-inactivation pattern.
CUL4B