Name of Article:
Description of a novel HLA-DQB1 allele, HLA-DQB1*06:126, in the Saudi stem cell donor registry
Fakhoury HA1, Alzahrani M2, Alaskar AS3, Hajeer AH2,4
Year of Publication:
- Department of Basic Sciences, College of Science and Health Professions, King Saud bin Abdulaziz University for Health Sciences, National Guard Health Affairs, Riyadh, Saudi Arabia.
- 2Saudi Stem Cell Donor Registry, King Abdullah International Medical Research Center, National Guard Health Affairs, Riyadh, Saudi Arabia.
- 3King Abdullah International Medical Research Center, Riyadh, Saudi Arabia.
- 4Department of Basic Medical Sciences, College of Medicine, King Saud bin Abdulaziz University for Health Sciences, National Guard Health Affairs, Riyadh, Saudi Arabia.
The human leukocyte antigen (HLA) genes are highly polymorphic and the list of new alleles continues to grow. The IMGT/HLA database (www. ebi.ac.uk/ipd/imgt/hla) has records of all HLA variants. HLA-DQ plays a central role in the immune system by presenting peptides derived from extracellular proteins. HLA matching is essential for successful bone marrow transplantation.
Formal written consent to participate in the Saudi Stem Cell Registry was obtained from all donors. The project was approved by the local Institutional Review Board at National Guard Health affairs, Saudi Arabia. A sample of peripheral whole blood was collected in a tube with ethylenediaminetetraacetic acid (EDTA). The buffy coat for all samples was stored at −80 ∘C until used. Total genomic DNA was extracted using QIAamp DNA Blood Mini Kit according to the manufacturer’s instructions (Qiagen, Hilden, Germany). HLA-DQ genotyping was carried out by Histogenetics (Ossining, NY) using high-resolution HLA sequence-based typing (SBT).
In this study, we describe a newallele HLA-DQB1*06:126 in an Arab volunteer for the Saudi Stem Cell Donor Registry (SSCDR). The nucleotide sequence of the novel allele has been submitted to GenBank with accession
number KC959352 and to the IMGT/HLA database with accession number HLA10300. The name HLA-DQB1*06:126 has been officially assigned by the World Health Organization HLA Nomenclature Committee in October 2013. This follows the agreed policy that, subject to the conditions stated in the most recent Nomenclature report, names will be assigned to new sequences as they are identified. The novel allele was included in the updated WHO Nomenclature Report and was made available in 3.15.0 release version of IMGT/HLA database.
HLA typing was performed for all the 6480 potential donors collected thus far. HLA-DQB1*06:126 differs from
HLA-DQB1*06:02:01 by a nonsynonymous C to T substitution at nucleotide position 1621 in Exon 2, resulting in an amino acid change from arginine to cysteine at codon 23. The allele most similar to the novel allele DQB1*06:126 is DQB1*06:02:01 which has not previously been detected in the Saudi population.