Propionic acidemia results from mutations in either of the two genes, PCCA or 
PCCB, that encode the two subunits of the propionyl-CoA carboxylase (PCC) 
enzyme. In this study, we report the identification and analysis of seven novel 
splicing mutations involving consensus donor and acceptor splice sites. Most of 
them were identified in patients with a Central Asian origin, and some present 
in several alleles, probably reflecting founder effects. The functional 
consequences of the splicing mutations were analyzed in patients' fibroblasts, 
as well as transcript quantification using real-time PCR methods. In the PCCA 
gene, two mutations were demonstrated to affect 5' splice sites (c.231+1G>C and 
c.1209+3A>G) and two 3' acceptor splice sites (c.1210delG and c.1430G>T), all 
causing skipping of the exons involved, with no detectable levels of normally 
spliced transcript. In the PCCB gene, all three mutations involved 5' donor 
splice sites-two affected exon 1 splicing (c.154_183+17del46 and c.183+2T>C), 
the latter activating a cryptic splice site in intron 1, and the remaining 
mutation (c.1498+2T>C) resulted in exon 14 skipping. The results highlight the 
necessity to perform transcript analysis in addition to genomic DNA sequencing 
to characterize the effect of splicing mutations and add relevant information on 
the genetic epidemiology of the disease.