Sickle cell disease (SCD) is the most prevalent life threatening blood monogenic disorder. Currently, there is no cure available, apart from bone marrow transplantation. Early and efficient diagnosis of SCD is key to disease management which would make considerable strides in alleviating morbidity and reducing mortality. However, the cost and complexity of diagnostic procedures like Sanger sequencing impede the early detection of SCD in a resource-limited setting. To address this, the current study demonstrates a simple and efficient proof-of-concept assay for detection of patients and carriers from extraction free non-invasive buccal swab samples by isothermal DNA Amplification coupled Restrictase-mediated cleavage (iDAR) . This study is a first of its kind reporting the use of buccal swab specimens for iDA in molecular diagnosis of a genetic disease all the while being cost effective and time saving with the total assay time of around 150 minutes at a cost of USD 5. Further, iDAR demonstrates 91.5% sensitivity and 100% specificity for detecting all three alleles; SS, AS and AA having 100% concordance with Sanger sequencing. The applicability of iDAR assay is further demonstrated with its adaptation to a one-pot reaction format, which simplifies the assay system. Overall, iDAR is a simple, cost-effective, precise and non-invasive assay for SCD screening with the potential for use in a limited resource setting.

The authors have declared no competing interest.

This work was supported by the Council for Scientific and Industrial Research (CSIR) grants (MLP2010 and HCP023) and Department of Biotechnology grant (BT/GET/119/SP31652/2020) Government of India (GoI) to SR. PT, PG, SG and NB are recipients of Senior Research Fellowship from Department of Biotechnology, Council of Scientific and Industrial Research, University Grant Commission and Indian Council for Medical Research, GoI respectively.

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Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology (CSIR-IGIB) All India Institute of Medical Sciences, New Delhi (AIIMS, New Delhi)

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