75. A FAMILY OF MATCHED PARENT-CHILD HLA HAPLOTYPES: A CASE STUDY FROM BAHRAIN

Abstract

Introduction Bone marrow transplant (BMT) is a medical procedure performed to replace the soft, fatty bone marrow that has been damaged or destroyed by disease, infection, or chemotherapy. Most bone marrow transplants are usually performed on patients with certain blood cancers (leukemias) and other blood disorders. Cases of fully matched offspring(s) with parents are very rare and would occur when both parents share at least one haplotype which is commonly seen in several generations of consanguineous marriages ( Hajeer et al. 2012 ). The probability of finding a full parent-child HLA match is higher in consanguineous marriages common in the Middle East, West Asia and North Africa ( Hamamy, 2011 ). We present a case of a unique family in Bahrain with four children (two sons and two daughters). The four siblings and their parents were tested for HLA to check whether they were a match with a family member who needed a bone marrow transplant after being diagnosed with Acute Myeloid Leukemia (AML). Materials and Methods Six DNA samples were extracted from peripheral blood using the Qiagen QIAamp DNA Mini Kit according to manufacturer's instructions (Qiagen, Hilden, Germany). The extracted DNA samples were quantified using the Qubit® 3.0 Fluorometer. A separate PCR protocol was set up for each locus to be amplified and for each individual sample to be tested. Successful amplicons were confirmed by a 1% agarose gel electrophoresis. Sequencing reactions were run with group specific and locus specific primers using the Conexio Genomics SBT Resolver kits. The sequenced products were purified using the ethanol precipitation method and capillary electrophoresis using the ABI 3130XL Genetic Analyzer (Applied Biosystems). The data was analysed using the CareDx Pty Ltd's ASSIGN™ SBT software. Results The results showed that of the four children both sons were a 100% match with the mother, while one of the two daughters was a 100% match with the father. Conclusion This case presents a unique situation where parents and children have fully matched HLA alleles due to a strong family history of consanguinity. This is the first case reported in Bahrain where children were found to be a 100% HLA-matched with their parents. Further studies are suggested to arrive to a broader conclusion to understand whether this is an isolated case or more of such cases would be found to be a trend in the Bahraini population.