ABSTRACT
ObjectiveTo study the molecular genetic mechanism of para-bombay phenotype in two individuals.MethodsThe proband was a female.When the proband donated blood,because the forward blood group wasn't coincident with her reverse blood group,the blood and saliva specimen from proband and her family members were sent to Guangzhou Blood Center for further identification.Routine serological techniques were used to determine proband's and her family members' blood group and ABH antigen in saliva.The coding regions of FUT1 and FUT2 gene,exon 6 and exon 7 of ABO gene were amplified by polymerase chain reaction using proband's and her family members' genomic DNA.All amplified products were analyzed after being directly sequenced.The two-base deletion regions of FUT1 gene were certified by cloning and haplotype sequencing.Results Proband's and her little brother's blood group were identified as para-bombay while other family members' blood group were normal.Two-base deletion heterozygous mutations of FUT1 gene were found in proband and her brother,AG deletion at position 547-552 and TT deletion at position 880-882,which caused a reading frame shift and a premature stop eodon.Meanwhile,880-882del TT heterozygous mutation was found in proband's grandfather and her father and 547-552del AG heterozygous mutation was found in proband's mother and her little sister.ResultsOf cloning and haplotype sequencing certified that these two-base deletion mutations occurred at 547-548 and 881-882 position respectively.Three new mutations were found in FUT2 gene,390C ＞ T,418A ＞ T and 749G ＞ A,which could cause the change of amino acid at position 140Ile ＞ Phe and 250Arg ＞ Gln.Conclusions Two-base deletion heterozygous mutations in different positions in FUT1 gene were found in 2 individuals,which maybe the molecular genetic mechanism of para-bombay phenotype.Heterozygous deletion mutation in one-strand DNA wouldn't change the ABO blood group.Three new mutations were also found in FUT2 gene.( Chin J Lab Med,2012,35:815-819)