OBJECTIVETo study the molecular genetic basis for p phenotype.

METHODSRed blood cell phenotype of the proband was characterized by standard serological technique. Exon 3 of the alpha (1,4) galactosyltransferase gene was amplified by polymerase chain reaction from genomic DNA of the proband. The amplified PCR products were excised and purified from agarose gels and direct sequenced.

RESULTSHomozygous single nucleotide G deletion at position 300 or 301 was found in the proband, which caused a reading frame shift at codon 101,resulting in a premature stop at codon 113. Parents of the proband were heterozygous carriers.

CONCLUSIONA novel single guanosine deletion at position 300 or 301 of alpha (1,4) galactosyltransferase gene was determined, which may be one facet of the molecular basis for p phenotype.