The need for more accurate and timely diagnosis in Fanconi anemia : a report from the international Fanconi anemia registry

The objective of this study was to address the need for early diagnosis of Fanconi anemia (FA), an autosomal recessive chromosomal instability syndrome characterized by a unique cellular hypersensitivity to DNA cross-linking agents, such as diepoxybutane, and by a high risk of malignancies. We analyzed data from 370 FA patients enrolled in the American Registry of the International FA Registry. Of these individuals, 220 had congenital malformations; the rest were ascertained based on hematologic abnormalities only or on clinical evaluation and screening following the diagnosis of an affected family member. The probands noted to have congenital malformations at the time of diagnosis were classified into two groups on the basis of their clinical presentation: (1) patients manifesting both congenital malformations and hematologic abnormalities (159 individuals); (2) patients manifesting congenital malformations only (61 individuals). The mean age of diagnosis was 6.6 years and 1.1 years for Groups 1 and 2, respectively. Thus, the majority of FA patients with congenital malformations were not diagnosed until after the onset of hematologic abnormalities. We also report central nervous system, gastrointestinal, and skeletal malformations which previously have not been included as part of the FA phenotype. Our review of the patients enrolled in the International FA Registry indicates that the FA phenotype is more variable than recognized previously. Testing for sensitivity to diepoxybutane to rule out a diagnosis of FA needs to be applied more widely in patients with congenital malformations. All siblings of affected probands also should have testing, because a lack of concordance of phenotype in affected siblings makes clinical diagnosis unreliable even within sibships. A more timely diagnosis of FA in the preanemic phase is needed to implement appropriate therapy and to enable parents to make informed reproductive decisions.