OBJECTIVE: To explore the molecular basis for a rare case with Para-Bombay AB blood type. METHODS: Serological method was used to determine the blood type of the proband. Exons 6 and 7 of the ABO gene and the coding regions of FUT1 and FUT2 genes were analyzed by direct sequencing. RESULTS: Serological results showed that the proband was a Para-Bombay AB subtype. His genotype was determined as ABO*A1.02/B.01. The proband was also found to harbor c.551-552delAG and c.881-882delTT of the FUT1 gene. For his four children, there were three type B and one type A, though the expression of the H type was normal. CONCLUSION The double deletions in the coding region of the FUT1 gene probably underlay the Para-Bombay blood type in the proband. Carrier of single-strand deletions may have a normal ABO phenotype.
ABO Blood-Group System/genetics* ; Alleles ; Fucosyltransferases/genetics* ; Genotype ; Humans ; Male ; Phenotype ; Sequence Analysis

Objective To analyze the clinical features and gene mutations types of 15 unrelated probands with coagulation factor Ⅴ(FⅤ)deficiency,and explore the possible molecular pathogenesis.Methods FⅤ activity(FⅤ∶C)and FⅤ antigen(FⅤ∶Ag)were detected by one-stage clotting and ELISA,respectively.All 25 exons of the F5 gene in the patients were amplified by PCR,and se-quenced directly.Haplotype analysis was performed with different polymorphisms on FⅤ.Protein modeling was applied to analyze the potential molecular mechanisms.Results Of the 5 probands with an FⅤ∶C greater than 10％,only 1 had minor bleeding symptoms.In the 10 probands with FⅤ∶C less than 10％,seven showed various bleeding manifestations.A total of 12 gene mutations locus were de-tected from 15 probands(8 gene mutations locus were novel mutations,and 1 was pathogenic polymorphism).An in silico analysis pre-liminarily investigated the potential pathogenic mechanism of the mutation.Modeling analysis showed that all the six missense mutations would lead to conformational alterations in the FⅤ protein.Among them,two(p.Ser1781 Arg and p.Asp96His)would decrease hydro-gen bonds.Conclusion The level of FⅤ in these probands with inherited FⅤ deficiency were associated with mutations in the respec-tive F5 gene,and the FⅤ levels strongly correlated with the probability of hemorrhage.

Objective:To analyze the genetic variants of two consanguineous Chinese pedigrees affected with Hereditary prokallikrein (PK) and High molecular weight kininogen (HMWK) deficiency and explore their molecular pathogenesis.Methods:A PK deficiency pedigree (10 individuals from 4 generations) and a HMWK deficiency pedigree (6 individuals from 3 generations) which were admitted to the First Affiliated Hospital of Wenzhou Medical University on December 3, 2021 and June 16, 2022, respectively were selected as the study subjects. Clinical data of the two pedigrees were collected, and the related coagulation indexes of the probands and their family members were determined. Genomic DNA of the two pedigrees was extracted from peripheral blood samples. This study was approved by the First Affiliated Hospital of Wenzhou Medical University (Ethics No. KY2022-R193).Results:The plasma PK activity of proband A, a 29-year-old female, and her brother were extremely low (< 1.0%). Proband B was a 66-year-old male with extremely low plasma HMWK activity (< 1.0%). Genetic sequencing revealed that the proband A and her brother had both harbored a homozygous c. 417_418insCATTCTTA (p.Arg140Hisfs*3) insertional variant in exon 5 of the KLKB1 gene, with her grandmother, maternal grandmother, father, mother, sister and son all carrying heterozygous insertion variant, and her ancestor father and husband are both wild-type. Proband B had harbored a homozygous c. 460C>A (p.Pro154Thr) missense variant in exon 4 of the KNG1 gene, and his son carries a heterozygous missense variant. All other members of the pedigree are wild type. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variants were respectively rated as pathogenic (PVS1+ PM2_Supporting+ PM4) and likely pathogenic (PS4+ PM2_Supporting+ PP3+ PP4). Conclusion:The c. 417_418insCATTCTTA (p.Arg140Hisfs*3) variant of the KLKB1 gene and the c. 460C>A (p.Pro154Thr) variant of the KNG1 gene probably underlay the decreased PK and HMWK activities in the two pedigrees, respectively.