Differentiation of Fanconi Anaemia (FA) from Idiopathic Aplastic Anaemia by Mitomycin -C (MMC) Stress Test

Introduction and Background:Fanconi Anaemia (FA), an autosomal recessive disorder is one of the most common amongst hereditary causes of idiopathic aplastic anaemia with a worldwide incidence of 1 in 1, 60,000 individuals. Apart from the haematological changes like pancytopenia and bone marrow failure, which are the most important clinical features, FA also presents with a variety of congenital anomalies and spontaneous chromosome instability. However, FA is difficult to diagnose on the basis of clinical features alone due to its heterogenous nature. Hypersensitivity to DNA cross linking agents like Mitomycin C (MMC), Diepoxybutane (DEB) is used as a differential diagnostic test while working up for aplasticanaemia.Aims and Objectives:Objective of our study was to throw light on the significance of Mitomycin stress test as a first line test in diagnosing FA while differentiating it from other causes of idiopathic aplastic anaemia. Since FA is a hereditary disease, an early identification of cases in at-risk families can help in haematological monitoring of the patients in these families.Materials and Methods:Patients of idiopathic aplastic anaemia with strong clinical suspicion of FA were taken up for chromosomal breakage evaluation by Mitomycin stress test (MMC Stress test) and resultswerecompared using samples from age and gender matched controls.Results and Discussion:1.Out of 17,4 patients showed chromosomal instability suggestive of Fanconianemia.2.On MMC stress test, we observed increased number of chromosomal breaks as compared to the controls. Also it was observed that patients showed triradial, quadriradial and complex chromosomal breakage figures in more than 90 percent of the cellsanalysed.Conclusion:Mitomycin induced stress test can be considered as a gold standard test in differentiating Fanconi anaemia patients from the other causes of aplasticanaemia.