Studies in mouse have demonstrated that haploinsufficiency of SUZ12 results in cerebellar herniation and an enlarged brainstem, accompanied by occipital cortical alterations and spina bifida (PMID:19535498). Somatic loss of function mutation in SUZ12 have been associated with T-ALL (PMIDs:22237151 and 22237106). However, germline loss of function mutations or focal deletions of SUZ12 have not been described. 5-10% of the NF patients show a large deletion including the SUZ12 gene. Haploinsuffiency of SUZ12 has been proposed to be responsible for the brain malformation, brain malfunction and/or congenital heart defects of these patients.