Mice deficient in SNF2H die after embryonic implantation (between E5.5 and E7.5, a checkpoint at which impaired proliferation is often associated with lethality) and have not been fully characterized58. The role of SNF2H-containing complexes in development is less clear than that of SNF2L-containing complexes, although the severe phenotype of Snf2h-null mice suggests that such complexes have crucial roles. An accessory subunit of the WICH complex, known as WSTF (Williams–Beuren syndrome transcription factor), is encoded in the 1.6-megabase haploinsufficient region of chromosome 7. This region is responsible for the genetic disorder Williams–Beuren syndrome in humans, a developmental disorder characterized by a specific form of mental ability or retardation combined with congenital cardiovascular disease and growth deficiency59. Wstf-haploinsufficient mice recapitulate the cardiovascular defects observed in human patients60. Hence, WICH complexes might be responsible for these phenotypes, through either their functions in regulating the replication of DNA or the assembly and structure of chromatin.
