RESUMEN
<p><b>OBJECTIVE</b>To explore molecular and genetic mechanism of 3 cases of para-Bombay blood group.</p><p><b>METHODS</b>The bood samples of proband and family members were selected to identify their blood groups with conventional serologic methods, and salivary components carrying the ABH antigens were detected. The coding regions of FUT1 as well as exon 6 and 7 of the ABO gene were amplified using polymerase chain reaction(PCR), and the FUT1 gene was directly sequenced.</p><p><b>RESULTS</b>All the 3 cases of proband were confirmed as para-Bombay blood group. Direct sequencing revealed h new2 (nt328G→A) and h1(nt 547 ΔAG) in FUT1 gene of the proband 1, and FUT1 genotype was h1/h new2. However, the genotypes of his parents were H/h1 and H/h new2, which were non-Bombay individuals. The FUT1 genotypes of proband 2 and 3 were h1h2 (nt 547 ΔAG) and h1h2 (nt 880 ΔTT), respectively.</p><p><b>CONCLUSION</b>The technology of molecular biology can be used to detect the base deletion mutations in FUT1 gene, which contributes to the analysis of molecular and genetic mechanism of para-Bombay blood group.</p>