OBJECTIVE: To study the characteristics of a novel variant of the α-1,3-N-acetylgalactosaminyltransferase gene in a family through serological and gene sequence analyses of a proband with ABO subtype and her family members. METHODS: Blood samples of the proband and four family members were collected. The ABO phenotypes were detected by serological methods, and the ABO blood group genotyping was performed by fluorescence PCR. Direct sequencing was carried out for exons 1-7 of the ABO gene in the proband and family members, and cloning sequencing was conducted for exons 6 and 7. RESULTS: The serological test showed that the blood group phenotype of the proband was Ael type, and the ABO blood group genotyping result was A/O. Sequencing results indicated that on the basis of the ABO*A1.01 sequence, there were simultaneous variations of c.467C>T and c.664G>A in exon 7 of the A allele, which belonged to a novel variation of the A allele and had been registered in GenBank with the accession number MZ076784.1. Family investigation revealed that the proband, her son and granddaughter all had this novel variation. CONCLUSION On the basis of the ABO*A1.01 sequence, the new variation of the combination of c.467C>T and c.664G>A in exon 7 is a heritable variation. It is speculated that this variation is the cause of the weakened expression of the A antigen.
Humans ; N-Acetylgalactosaminyltransferases/genetics* ; ABO Blood-Group System/genetics* ; Pedigree ; Female ; Genotype ; Male ; Exons ; Alleles ; Phenotype

OBJECTIVE: To explore the clinical phenotype and genetic etiology of a child with Ehlers-Danlos syndrome, spondylodysplastic type 2 (EDSSPD2). METHODS: A child who was admitted to the Children's Medical Center of the Affiliated Hospital of Guangdong Medical University in July 2024 for "delayed motor development for 1 and a half year" was selected as the study subject. Clinical data of the child was collected, including medical history, family history, and results of auxiliary examinations. Peripheral venous blood samples were collected from the child and his two brothers and both parents. Genomic DNA was extracted from the child and his family members and subjected to whole-exome sequencing (WES) and copy number variation (CNV) analysis. Sanger sequencing was used to verify the parental origin of the candidate variants. Multiple protein function prediction software tools, including SIFT, PolyPhen-2, and REVEL, were used to assess the impact of candidate variants on the protein function. Based on protein database information from UniProt, a two dimensional structural schematic of the target protein was generated. The pathogenicity of the variants was classified based on the guidelines from the American College of Medical Genetics and Genomics (ACMG). Relevant literature on the B3GALT6 gene variants leading to EDSSPD2 was retrieved from CNKI, Wanfang Data Knowledge Service Platform, and PubMed databases. The procedures followed in this study were reviewed and approved by the Medical Ethics Committee of Affiliated Hospital of Guangdong Medical University (Ethics No.：PJ2021-097). RESULTS: The proband was a 2-year-old male with an onset in infancy. The main clinical manifestations included loose skin, scoliosis and kyphosis, generalized hypermobility of joints, and motor developmental delay. WES has revealed two compound heterozygous variants of the B3GALT6 gene (NM_080605.4): c.766C>T (p.Arg256Trp) and c.962G>A (p.Cys321Tyr). Sanger sequencing verification showed that the c.766C>T and c.962G>A variants were respectively derived from his phenotypically normal father and mother. Bioinformatics analysis showed that for the c.766C>T (p.Arg256Trp) variant, the Arg256 site is located within the galactosyltransferase catalytic domain (GalT domain) of the β3GalT6 protein. According to the ACMG guidelines, the c.766C>T variant was classified as a likely pathogenic (PS3+PM2_supporting+PM3+PP3), and the c.962G>A was classified as a variant of unknown significance (PM2_Supporting+PM3+PP3). By following the pre-set literature retrieval strategy, a total of 12 articles related to B3GALT6 gene variants were identified (11 English and 1 Chinese), which involved a total of 71 patients. Among these, 4 reports (involving 20 patients) involved B3GALT6 gene variants leading to EDSSPD2. Among the 18 live-born EDSSPD2 patients (including the proband in this study), common clinical manifestations have included scoliosis (88.9%, 16/18), generalized hypotonia (83.3%, 15/18), and soft and lax skin (66.7%, 12/18). Some patients already showed skeletal abnormalities on prenatal ultrasound scan (22.2%, 4/18), while a few presented with cervical instability (16.7%, 3/18). One child had deceased at 18 months of age due to hypoxia caused by tracheomalacia and tracheal compression due to scoliosis. Among the 23 reported EDSSPD2 related B3GALT6 variant sites, missense variants were the most common (78.3%, 18/23), followed by nonsense variants (21.7%, 5/23). CONCLUSION Above finding has enriched the clinical and mutational spectra of EDSSPD2. Early genetic testing has important clinical value for the diagnosis, differential diagnosis, and genetic counseling of this disease.
Humans ; Male ; Ehlers-Danlos Syndrome/genetics* ; Pedigree ; N-Acetylgalactosaminyltransferases/genetics* ; Asian People/genetics* ; DNA Copy Number Variations ; Exome Sequencing ; Female ; Child ; Child, Preschool ; Phenotype ; Mutation ; China ; East Asian People ; Galactosyltransferases

OBJECTIVE: To explore the genetic basis for a Chinese pedigree affected with recurrent fetal hydrocephalus. METHODS: A couple who had presented at the Affiliated Hospital of Putian College on March 3, 2021 was selected as the study subject. Following elective abortion, fetal tissue and peripheral blood samples were respectively obtained from the abortus and the couple, and were subjected to whole exome sequencing. Candidate variants were verified by Sanger sequencing. RESULTS: The fetus was found to harbor compound heterozygous variants of the B3GALNT2 gene, namely c.261-2A>G and c.536T>C (p.Leu179Pro), which were inherited from its father and mother, respectively.According to the guidelines of American College of Medical Genetics and Genomics, both variants were classified as pathogenic (PVS1+PM2_Supporting; PM3+PM2_Supporting+PP3+PP4). CONCLUSION The compound heterozygous variants of the B3GALNT2 gene probably underlay the α-dystroglycanopathy in this fetus. Above results have provided a basis for genetic counseling of this pedigree.
Female ; Humans ; Pregnancy ; Aborted Fetus ; Asian People/genetics* ; East Asian People ; Fetus ; Genetic Counseling ; Mutation ; N-Acetylgalactosaminyltransferases ; Pedigree ; Walker-Warburg Syndrome/genetics*

OBJECTIVE: To explore the genetic basis for a Chinese pedigree with a novel ABO subtype. METHODS: The proband and his family members were subjected to serological analysis, and their genotypes were determined by fluorescence PCR and direct sequencing of the coding regions of the ABO gene. Exons 6 to 7 of the ABO gene were also subjected to clone sequencing for haplotype analysis. RESULTS: The proband was determined as an AxB subtype. By fluorescence PCR, he was typed as A/B. Clone sequencing has revealed a insertional mutation c.797_798 insT in exon 7 of the ABO gene, which yielded a novel allele. Pedigree analysis confirmed that the novel ABO*A1.02 allele carried by the proband and his sister was inherited from their father. The c.797_798insT mutation has been submitted to GenBank with an accession number of MK125137. CONCLUSION The c.797_798insT mutation of exon 7 of the ABO gene probably has led to weakened expression of A antigen.
ABO Blood-Group System/genetics* ; Alleles ; China ; Genotype ; Humans ; Male ; Mutation ; N-Acetylgalactosaminyltransferases/genetics* ; Pedigree

OBJECTIVETo explore the effect of alpha-1,3-N-acetylgalactosaminyltransferase gene variants on A antigen expression in a family where a member was suspected for a rare A3 subtype of the ABO variant.

METHODSSerological assay was carried out to determine the ABO blood group of the proband and his family members. To determine the haploid of the alpha-1,3-N-acetylgalactosaminyltransferase gene of the proband, DNA was extracted and genotyped with sequence-specific primer PCR (PCR-SSP) followed by direct sequencing and cloning of exons 6 and 7 of the ABO locus.

RESULTSWeak A antigen was detected on red blood cells of the proband, while anti-A and anti-B antibodies were detected in his serum. DNA sequencing showed a 261delG mutation in exon 6, and two heterozygote mutations (467C>T and 745C>T) in exon 7 of the alpha-1,3-N-acetylgalactosaminyltransferase gene. Haplotype analysis has identified two alleles A307 and O01. Compared with the A101 allele, the A307 allele has harbored two nucleotides changes (467C>T and 745C>T), which resulted in substitution of two amino acids (P156L and R249W).

CONCLUSIONThe 467C>T and 745C>T mutations of the alpha-1,3-N-acetylgalactosaminyltransferase gene can result in an A307 phenotype with reduced expression of A antigen.

ABO Blood-Group System ; genetics ; Alleles ; Child ; Humans ; Male ; Mutation ; genetics ; N-Acetylgalactosaminyltransferases ; genetics ; Sequence Analysis, DNA ; methods

OBJECTIVETo explore the effect of variants of alpha-1,3-N-acetylgalactosaminyltransferase of the ABO gene on A antigen expression.

METHODSThree samples were assayed by serological method. The extracted DNA was genotyped by sequence-specific primer polymerase chain reaction (SSP-PCR) and direct sequencing. To identify haploid of the ABO gene, clones for exons 6 and 7 of the ABO locus were analyzed.

RESULTSAll of the three samples were identified as the Ael subgroup, among which were found to carry the Ael08 and O01 alleles, while another was confirmed to harbor the Ael08 and O04 alleles. Compared with the A101 allele, two nucleotide alterations (467C>T and 804insG) at exon 7 have resulted in amino acid substitution P156L and frameshift from position 269.

CONCLUSION467C>T and 804insG variants of the alpha-1,3-N-acetylgalactosaminyltransferase gene probably underlie the Ael phenotype.

ABO Blood-Group System ; genetics ; Alleles ; Female ; Humans ; Male ; N-Acetylgalactosaminyltransferases ; genetics

OBJECTIVETo analyze the serological features and related blood group genes of a donor with A subtype of the ABO blood type.

METHODSThe ABO blood group of the sample was determined, in addition with the activity of blood group glycosyltransferase and blood group secretory substances. Sanger sequencing was adopted to analyze the genotype of the blood group.

RESULTSThe proband was identified as A subtype (non-secretory type), with no detectable activities of a 1, 3-N-acetylgalactosyltransferase. DNA sequencing has identified a number of mutations including nt.261del/G and 297A/A of exon 6, and nt.467C/T, 806T/C and 1009A/G of exon 7. Clone sequencing has confirmed that the nt.806T>C exists at one allele and was a novel mutation. The proband genotype was A205/Onew (806T>C). The nt.806T>C of the exon 7 was confirmed to be a novel mutation, which was given a GenBank accession number KP341759. Family study showed that the genotype of the proband's father was Onew (806T>C)/O02, and that of his mother was A101/A205. The novel mutation of the proband has derived from his father.

CONCLUSIONThe reduced A antigenicity of the sample was due to the A205 subtype allele and the presence of a novel O allele.

ABO Blood-Group System ; genetics ; Adult ; Base Sequence ; Blood Grouping and Crossmatching ; Exons ; Female ; Genotype ; Humans ; Male ; Molecular Sequence Data ; Mutation ; N-Acetylgalactosaminyltransferases ; genetics ; metabolism

OBJECTIVETo study the serological characteristics and molecular mechanism for a rare Pk phenotype of the P1Pk blood group system.

METHODSThe blood group of the proband was identified by serological techniques. The coding region and flanking intronic sequences of the β-1,3-N-acetylgalactosyltransferase gene (B3GALANT1) associated with the Pk phenotype were analyzed using polymerase chain reaction sequence-based typing.

RESULTSThe proband was identified as having a rare Pk phenotype including anti-P in her serum. The blood group of her daughter and husband showed a P2 phenotype. The nucleotide sequences of the B3GALANT1 gene of her husband and two randomly-chosen individuals were the same as the reference sequence (GenBank AB050855). Nucleotide position 433 C>T homozygous mutation in the B3GALANT1 was found in the proband, which has resulted in a stop codon at amino acid position 145, which may produce a premature protein capable of decreasing or inhibiting the activity of the β -1,3-N-acetylgalactosyltransferase. The nucleotide position 433 C/T heterozygous in the B3GALANT1 was found in her daughter.

CONCLUSIONThe Pk phenotype resulted from 433 C>T mutation in the B3GALANT1 gene has been identified.

ABO Blood-Group System ; genetics ; Adult ; Base Sequence ; Blood Grouping and Crossmatching ; Female ; Genotype ; Humans ; Male ; Molecular Sequence Data ; N-Acetylgalactosaminyltransferases ; genetics ; Pedigree ; Phenotype ; Point Mutation

OBJECTIVETo investigate the molecular basis of an individual featuring weak A phenotype of ABO blood group system.

METHODSSerologic investigations, serum transferases activity assay and absorption-elution test were carried out to identify the ABO blood group. The 7 exons and flanking introns of ABO glycosyltransferase gene were amplified with polymerase chain reaction (PCR). The products were sequenced bidirectinally following enzyme digestion. Haplotypes of exons 6 and 7 of the ABO gene were analyzed.

RESULTSA weak A antigen was identified on red blood cells of the proband. Eight heterozygous sites in exons 6 and 7 (261delG 297A/G, 421C/T, 467C/T, 646T/A, 681G/A, 771C/T, 829G/A) of the ABO gene were identified. Based on haplotype analysis, one allele was determined as O02, while a novel mutation 421T>C was identified in another allele, which resulted in the amino acid change Ser141Pro of the A glycosyltransferase.

CONCLUSIONAbove results suggested that amino acid substitutions resulted from a novel mutation 421T>C of the ABO gene may decrease the enzymatic activity and result in the weak A phenotype.

ABO Blood-Group System ; genetics ; Adult ; Alleles ; Female ; Humans ; Mutation ; N-Acetylgalactosaminyltransferases ; genetics

OBJECTIVETo explore the molecular basis for a rare Ax13B phenotype of the ABO subtype.

METHODSSerological assays were carried out to characterize the erythrocyte phenotype of the discrepant sample. Exons 6 and 7 of the ABO gene were amplified with polymerase chain reaction and subjected to direct sequencing. The amplicons were also cloned to separate the two alleles.

RESULTSBoth A and B antigens were detected on the red blood cells of the proband, and anti-A antibody was detected in the serum. The serological phenotype of the sample was identified as AxB. DNA sequencing showed heterozygous status for 297AG, 526CG, 657CT, 703AG, 796AC, 803GC, 930GA and 940AG in exons 6 and 7. After cloning and sequencing, two alleles Ax13 and B101 were obtained. The sequence of Ax13 showed a nucleotide change (A to G) at position 940.

CONCLUSIONThe 940A>G mutation of the α-1,3-N-acetylgalactosaminyltransferase gene has resulted in the reduced expression of A antigen.

ABO Blood-Group System ; genetics ; Alleles ; Base Sequence ; Blood Grouping and Crossmatching ; methods ; Exons ; genetics ; Genotype ; Genotyping Techniques ; methods ; Heterozygote ; Humans ; Male ; N-Acetylgalactosaminyltransferases ; genetics ; Phenotype ; Point Mutation ; Sequence Analysis, DNA ; methods