DEB test for Fanconi anemia detection in patients with atypical phenotypes.
Pancytopenia, hyperpigmentation, small stature, congenital abnormalities, and predisposition to neoplasia characterize Fanconi anemia (FA). The clinical phenotype is extremely variable, therefore the diagnosis is frequently delayed until the pancytopenia appears, making diagnosis difficult on the basis of clinical manifestations alone. Hypersensitivity of FA cells to the clastogenic effect of diepoxybutane (DEB) provides a unique marker for the diagnosis before the beginning of hematological manifestations. Our aim in this study was to detect FA in children with atypical manifestations to define which conditions should be routinely included in the DEB test screening. We performed the chromosomal breakage test in 34 patients with probable FA and 83 patients with clinical conditions that could suggest FA, but are not usually screened by the DEB test: 20 patients with aplastic anemia, 20 patients with VACTERL association, 20 with radial ray abnormalities, 7 with tracheo-esophageal fistulae, 12 with anal atresia, and 4 with myelodysplastic syndrome. We found 18 DEB-positive patients: 12 were in the group of probable FA and 6 in the other groups. Among the last ones: three were included because of aplastic anemia, without any other sign of FA, however when re-examined, other anomalies were detected. The third patient had anal atresia, renal hypoplasia, pre-axial polydactyly, and normal blood cell counts and was diagnosed as having VACTERL association. The other two patients lacking physical or hematological signs were identified among the group of radial ray abnormalities. Thus, our results highlight the need to increase the number of abnormalities indicating need for a DEB test. Delay in the diagnosis of FA may have serious consequences for the patients and their family members.
Esmer
Carmen
C
Department of Research in Human Genetics, National Institute of Pediatrics, Insurgentes Sur 3700-C, 04530 Mexico City, DF, Mexico.
Sánchez
Silvia
S
Ramos
Sandra
S
Molina
Bertha
B
Frias
Sara
S
Carnevale
Alessandra
A
D000328:Adult; D000741:Anemia, Aplastic / Q000175:diagnosis / Q000235:genetics; D016022:Case-Control Studies; D019457:Chromosome Breakage; D003937:Diagnosis, Differential; D004852:Epoxy Compounds; D004933:Esophageal Atresia / Q000209:etiology; D005199:Fanconi Anemia / Q000150:complications / Q000175:diagnosis* / Q000235:genetics*; D005260:Female; D005820:Genetic Testing / Q000379:methods*; D006801:Humans; D008297:Male; D009153:Mutagens; D010641:Phenotype; D011379:Prognosis; D014138:Tracheoesophageal Fistula / Q000209:etiology
D004852:Epoxy Compounds; D009153:Mutagens; C007366:diepoxybutane