The EIF3S3 gene encoding the p40 subunit of the translation initiation factor eIF3 has eight exons and maps to the Langer-Giedion syndrome chromosomeregion on 8q24, but is not the TRPS1 gene

We have mapped the gene encoding the p40 subunit of the eukaryotic translat ion initiation factor eIF3 (EIF3S3) close to the distal border of the minim al critical region for tricho-rhino-phalangeal syndrome type I (TRPS I) on human chromosome 8q24. Because this location makes EIF3S3 a candidate for t he TRPS1 gene, we have determined the genomic structure of the EIF3S3 gene and searched for gene deletions and mutations in patients with TRPS I. The gene has eight exons and is transcribed from telomere to centromere. No del etion could be detected in 32 unrelated patients with an apparently normal karyotype. Sequence analysis of all exons in 15 unrelated patients did not reveal any point mutation either. Our data exclude EIF3S3 as the TRPS1 gene .