Spectrum of mutations in a cohort of UK patients with ADA deficient SCID: Segregation of genotypes with specific ethnicities

•We retrospectively analysed 46 patient samples known to have ADA deficient SCID for ADA mutations.•We discovered 9 previously unreported mutations.•We categorised the phenotype-genotype correlations according to a previously described system.•We identified the most prevalent mutations in our UK cohort.•We linked specific mutations with ethnicity.

Severe combined immunodeficiency (SCID) arises from a number of different genetic defects, one of the most common being mutations in the gene encoding adenosine deaminase (ADA). In the UK, ADA deficient SCID compromises approximately 20% of all known cases of SCID. We carried out a retrospective analysis of the ADA gene in 46 known ADA deficient SCID patients on whom DNA had been stored. Here, we report a high frequency of two previously reported mutations and provide a link between the mutations and patient ethnicity within our patient cohort. We also report on 9 novel mutations that have been previously unreported.