Structure of the gene mutated in glycogen storage disease type Ib

We report the structure of the human gene encoding the putative glucose 6-p hosphate translocase that is mutated in glycogen storage disease type Ib. N orthern blots showed that the encoded 2.4 kb mRNA is mainly expressed in li ver and in kidney, but is also present, although in barely detectable amoun ts, in leucocytes. The gene contains nine exons, one of which (exon 7) is n ot present in human liver or leucocyte RNA. RT-PCR analysis of mouse RNA in dicates that exon 7, which is 63 bp long compared with 66 bp in man, is not expressed in liver and kidney but well in heart and brain. 5'-RACE and RNa se protection assays performed on RNAs from human liver, kidney and leucocy tes indicated the presence of two main regions of transcription start at si milar to-200 and -100 bp with respect to the initiator ATG. (C) 1999 Elsevi er Science B.V. All rights reserved.