TGFB1 and cranioectodermal dysplasia: In 2000, discovery that TGFβ1 mutation causes CED, together with subsequent family studies, confirmed the disorder's variable expressivity by documenting asymptomatic family members.(43,44) Following reports of higher plasma TGFβ1 levels in individuals with a -509T allele, Campos-Xavier et al.(68) in 2001 investigated whether TGFβ1 polymorphisms explain the variable penetrance of CED.