The novel gene, Diphor-1, was recently cloned from rat kidney and
shown to increase phosphate
uptake in cells when co-expressed with a Na+-Pi cotransporter,
indicating that it may play a
substantial role in cellular phosphate balance. Previously, the phosphate
wasting disorder, autosomal
dominant hypophosphatemic rickets (ADHR) was mapped to chromosome 12p13
by linkage
analysis. In the present work, PDZK1, a PDZ domain-containing protein highly
homologous to rat
Diphor-1, was shown to be expressed in human kidney. Based upon its sequence
similarity to rat
Diphor-1, we considered PDZK1 a feasible candidate gene for ADHR. PDZK1
was found to localize
to human chromosome 1q21, thereby ruling it out as a candidate for ADHR.