Genetic analysis of a Chinese pedigree with an allele dropout at the HLA-B locus / 中华医学遗传学杂志

OBJECTIVE@#To delineate a deletional mutation of the HLA-B gene in a Chinese pedigree.@*METHODS@#A female patient with acute myeloid leukemia who had visited Liuzhou People's Hospital in April 2022 was selected as the study subject. Routine human leukocyte antigen (HLA) was determined by using PCR-sequence specific oligonucleotide polymorphism (PCR-SSOP) and PCR-sequence-based typing (PCR-SBT) methods. Next generation sequencing (NGS) was used to validate the candidate variant in the HLA-B gene.@*RESULTS@#The PCR-SBT and SSOP results for the HLA-B locus were inconsistent for the patient and her daughter. The SSOP results of the two individuals were HLA-B*35:01, 40:02 and HLA-B*35:01, 40:01, respectively. However, the PCR-SBT results has indicated a mismatch with the nearest HLA-B*35:01 at exon 4. NGS results showed that the HLA-B*35:01 had a 9 bp deletion in the intron 5. The patient's husband was HLA-B*40:01, 58:01, which was normal.@*CONCLUSION@#The variant in intron 5 of the HLA-B gene in this pedigree has mapped to a primer-binding region for the SBT reagent, which has affected the accuracy of PCR-SBT results.

Identification of a novel HLA-DQB1*03 allele caused by variant of a single nucleotide / 中华医学遗传学杂志

OBJECTIVE@#To delineate the characteristics of a novel HLA-DQB1 allele identified during routine HLA matching in a leukemia family.@*METHODS@#The mother and brother of the patient were subjected to PCR sequence-specific oligonucleotide probe (SSOP), PCR sequence-based typ1ing (SBT), as well as next-generation sequencing (NGS).@*RESULTS@#PCR-SBT revealed that the patient's mother and brother's HLA-DQB1 sequences did not fully match with any known allele combination. NGS revealed that the novel allele has differed from the closest matched DQB1*03:02 with a T>G substitution at position 233 in exon 2, which resulted in substitution of Valine at codon 46 by Glycine. Pedigree analysis confirmed that the novel HLA-DQB1 allele was inherited from his mother.@*CONCLUSION@#A novel HLA-DQB1 allele has been identified through next generation sequencing and was officially named as HLA-DQB1*03:362 by the World Health Organization HLA Factor Nomenclature Committee.

Analysis and verification of a HLA-DQB1*03:90N allele with a single base deletion / 中华医学遗传学杂志

OBJECTIVE@#To verify a HLA-DQB1*03:90N allele and method to improve the accuracy of HLA typing.@*METHODS@#A total of 2265 hematopoietic stem cell donors from Shenzhen Branch of China Marrow Donor Program in 2018 were initially detected by a PCR sequence-specific oligonucleotide probe (SSOP) method. Among these, a rare HLA-DQB1 allele was identified by sequence-based tying (SBT) and Ion Torrent S5 next generation sequencing (NGS).@*RESULTS@#The SSOP typing result suggested the HLA-DQB1 to be a rare allele, while an insertion and a deletion was suspected in its exon 2 by SBT, which were confirmed by NGS as DQB1*03:90N and DQB1*06:01, respectively.@*CONCLUSION@#Rare alleles suspected by the SSOP method should be verified by other methods to ensure the accuracy of HLA genotyping. Rare alleles formed by deletions can be detected by NGS with accuracy.

Distribution of KIR/HLA alleles among ethnic Han Chinese patients with hepatocellular carcinoma from southern China / 中华医学遗传学杂志

OBJECTIVE@#To assess the association of KIR/HLA alleles with hepatocellular carcinoma (HCC) and hepatitis B virus (HBV) infection among ethnic Han Chinese patients from southern China.@*METHODS@#For 95 patients with HCC and 171 healthy controls, the genotype of HLA-C alleles was determined with a PCR sequence-specific oligonucleotides typing method on an Illumina GenDx NGSgo platform. Genotypes comprised of HLA-C and KIR gene alleles were also subjected to statistical analysis.@*RESULTS@#In total 16 KIR genes (2DL2, 2DS2, 2DS3, 2DS5, 3DS1, 2DS1, 2DL5, 2DS4, 3DL1, 3DP1, 2DL3, 2DP1, 3DL3, 2DL1, 3DL2 and 2DL4) were discovered in the two groups. The frequencies of KIR2DL3 alleles and combinational genotypes of KIR2DL3/HLA-C1C2 were significantly lower in the patient group compared with the controls (0.9368 vs. 0.9883, χ²>3.84; P3.84; P<0.05, RR = 0.03). The frequency of HLA-C2C2 genotype of the patient group was significantly lower than that of the controls (0.0316 vs. 0.2690, P<0.05, RR = 0.09), while the frequency of HLA-C1C2 genotype was significantly higher than that of the controls (0.2316 vs. 0.0058, P<0.05, RR = 51.23).@*CONCLUSION@#Above results suggested that the KIR2DL3 allele is associated with lower risk for HCC. There may be individual difference in patients with HCC and HBV infection but various combinations of KIR/HLA alleles.