OBJECTIVETo explore genetic background of a pedigree with a rare p phenotype from Guangdong province.

METHODSThe rare p phenotype was identified by a conventional serologic method. With genomic DNA of proband and family members extracted, exon 3 of alpha-(1,4)galactosyltransferase (A4GALT) gene was amplified with PCR and analyzed by direct sequencing. The mutation found in the pedigree was screened in a normal population using direct sequencing.

RESULTSThe proband and 4 family members with the rare p phenotype have all carried a point mutation c.100G>A (p.Val34Ile) in combination with a deletion-insertional mutation c.418_428del11ins34(p.Gln139Trpfs*72), which renders a compound mutation of A4GALT gene. One family member with P2 phenotype has carried a same heterozygous mutation. Of the 100 healthy donors, 5 have carried a heterozygous point mutation c.100G>A, and none carried the deletion-insertional mutation c.418_428del11ins34.

CONCLUSIONThe rare p phenotype of the pedigree has resulted from a compound mutation of the A4GALT gene, which is in keeping with a recessive inheritance pattern of the p phenotype.