OBJECTIVE: To explore the molecular reasons of weak expression of B antigen on the red cell. METHODS: Serological test for blood group was carried out, including red cell and plasma grouping, and anti-A1 and anti-H testing, and confirming weak A or B antigens by adsorption and elution. Exons 1-7 were sequenced directly, and one of them was cloned and sequenced. RESULTS: All of the 23 samples showed the weak B antigen by serological method. The alleles of the subgroups were identified by DNA sequencing, including 2 Bel subgroup, 4 B3 subgroup, 14 Bw subgroup, 2 CisAB subgroup and a novel allele. The novel allele showed a nucleotide substitution 662G>A in the exon 7, and the sequence was submitted to Blood Group Antigen Gene Mutation Database, and the novel allele was named Bel10. CONCLUSION Nucleotide substitution in exon results in blood subgroup, which showed that the antigens were weakened, and Bw phenotype was the most frequently subgroup.
ABO Blood-Group System/genetics* ; Alleles ; Exons ; Genotype ; Humans ; Nucleotides ; Phenotype

Objective:To investigate the prevalence of cataracts, the surgical coverage, and postoperative visual acuity of adults in Ningxia.Methods:A cross-sectional study using multistage cluster random sampling was conducted.Ten survey sites in Ningxia were selected and the population aged 18 years and over was surveyed with questionnaire, height and weight measurements, visual acuity, intraocular pressure, fundus photography and slit-lamp examinations.Cataract prevalence and its influencing factors were analyzed.Cataract prevalence, surgical coverage and presenting visual acuity (PVA) and best corrected visual acuity (BCVA) after surgery were investigated in different age groups of the examined population.The study adhered to the Declaration of Helsinki and was approved by the Ethics Committee of the People's Hospital of Ningxia Hui Autonomous Region (No.[2023]-LL-010).Participants signed informed consent prior to the examination.Results:A total of 6 145 people should be examined, and 5 721 people were actually examined, with an examination rate of 93.10%.The study population consisted of 2 558 males, accounting for 44.71%, and 3 163 females, accounting for 55.28%, with ages ranging from 18 to 93 years old and an average age of (64.27±13.48) years.Among them, 1 180 patients diagnosed with cataract, with a cataract prevalence of 20.62%.The prevalence of cataract increased with age and decreased with education level, showing statistically significant differences ( χ2=1 091.32, 581.92; both at P<0.01).The prevalence of cataract was significantly higher among people with hypertension, diabetes mellitus, hyperlipidemia, and coronary heart disease than those without these diseases ( χ2=274.65, 118.15, 78.05, 182.71; all at P<0.01).Cataract surgery was performed in 245 cases in the cataract patient population, with a surgical coverage rate of 20.76%.Of the 245 cases, 229 cases were implanted with IOLs, with an implantation rate of 93.40%.The social burden rate of cataract blindness was 2.29%, and increased with age.Of the 339 eyes that underwent cataract surgery, 241 had a PVA≥0.3, accounting for 71.09%, and 272 had a BCVA≥0.3, accounting for 80.24%. Conclusions:In Ningxia, cataracts are still the main cause of vision impairment and blindness in the elderly, and the social burden rate of cataract blindness is high.Moreover, the coverage rate of cataract surgery is low, so both the coverage and quality of surgery need improvement.