LAUSR

W hile investigating D zygosity, Perco and colleagues found in 2003 a variant of the downstream Rhesus box with a novel RHD allele in a blood donor from a Caucasoid population. This D1C–c1E–e1 sample showed a serologic weak D phenotype. Because the serology and RHD structure were compatible with the definition of a molecular weak D type, the allele was assigned weak D type 29. The 2918 nucleotides of the Rhesus box (GenBank AF469473) represented the sequence of a downstream connected to an upstream Rhesus box. A second example of weak D type 29 was observed in Tunisia among 448 samples that were D– by the indirect antiglobulin test. A nucleotide sequence FR745438.1 closely resembling weak D type 29 with one additional missense mutation and lacking one silent mutation was reported in 2010. None of these reports documented a detailed serologic description or the RH haplotype involved. The nucleotide variations of weak D type 29 were dispersed throughout the RHD gene and could neither be explained easily by a few mutation events nor fitted into one of the Eurasian D and African weak D type 4 clusters. We collected fresh samples from the Tunisian donor and the family of the original donor FR745438 to resolve both RHD and RHCE alleles and describe the serology. A new RH haplotype was documented.