Next generation sequencing of an australian family to identify the genetic basis of a rare blood group antigen

Abstract

<h3>Aim</h3> The SARAH red blood cell (RBC) antigen has been described in two families world-wide and has recently been implicated in a case of severe haemolytic disease of the fetus and newborn (HDFN). This study aimed to identify the genetic basis of SARAH. <h3>Methods</h3> DNA samples were collected from nine family members (six SARAH positive) from three generations. Samples were exome sequenced using the Agilent SureSelect All Exon v4 + UTR kit on an Illumina HiSeq2000. Sequence alignment was performed with Illumina CASAVA vl.8.2, mapping to the reference genome HG19. <h3>Results</h3> Sequencing identified 73 782 SNVs common among all family members. SNV filtering excluded SNVs with a NCBI dbSNP ID, non-protein coding SNVs, and SNVs not present in all six positive family members only. Following filtering, one SNV in the Glycophorin A (<i>GYPA)</i> gene was identified. This SNV is not in the 1000 Genomes Project (1000G) or Exome Sequencing Project (ESP6500) databases, further confirming this SNV is novel and of low-frequency. <h3>Discussion</h3> A genetic basis for SARAH was identified by utilising next generation sequencing of related individuals. This approach has application in investigations relating to other rare phenotypes or diseases of unknown genetic basis.