Two brothers with presumed Baller-Gerold syndrome, one of whom was previously diagnosed with the association of vertebral, cardiac, renal, limb anomalies, anal atresia, tracheo-esophageal fistula (VACTERL) association with hydrocephalus, were evaluated for chromosome breakage because of severe thrombo cytopenia in one of them. Spontaneous and clastogen-induced breakage was markedly increased in both patients as compared to control individuals. Clinical manifestations and chromosome breakage, consistent with Fanconi anemia, in patients with a prior diagnosis of either Baller-Gerold syndrome, reported earlier in one other patient [Farrell et al., 1994: Am J Med Genet 50:98-99], or with VACTERL association with hydrocephalus, recently reported in 3 patients [Toriello et al., 1991: Proc Greenwood Genet Center 11:142; Porteus et al., 1992: Am J Med Genet 43:1032-1034], underline the clinical heterogeneity of Fanconi anemia and raise the question of whether these syndromes are distinct disorders or phenotypic variations of the same disease.