Deficiency of propionyl CoA carboxylase (PCC), a dodecamer of alpha and beta 
subunits, causes inherited propionic acidemia. We have studied, at the molecular 
level, PCC in 54 patients from 48 families comprised of 96 independent alleles. 
These patients of various ethnic backgrounds came from research centers and 
hospitals in Germany, Austria and Switzerland. The thorough clinical 
characterization of these patients was described in the accompanying paper 
(Grünert et al. 2012). In all 54 patients, many of whom originated from 
consanguineous families, the entire PCCB gene was examined by genomic DNA 
sequencing and in 39 individuals the PCCA gene was also studied. In three 
patients we found mutations in both PCC genes. In addition, in many patients 
RT-PCR analysis of lymphoblast RNA, lymphoblast enzyme assays, and expression of 
new mutations in E.coli were carried out. Eight new and eight previously 
detected mutations were identified in the PCCA gene while 15 new and 13 
previously detected mutations were found in the PCCB gene. One missense 
mutation, p.V288I in the PCCB gene, when expressed in E.coli, yielded 134% of 
control activity and was consequently classified as a polymorphism in the coding 
region. Numerous new intronic polymorphisms in both PCC genes were identified. 
This study adds a considerable amount of new molecular data to the studies of 
this disease.