Improved gene therapy constructs for the treatment of propionic acidemia caused by mutations in propionyl-coa carboxylase alpha

A polynucleotide expression cassette comprising:

• (a) synthetic propionyl-CoA carboxylase subunit a (PCCA) polynucleotide (synPCCA) selected from the group consisting of:
• (i) a polynucleotide comprising the nucleic acid sequence of any one of SEQ ID NOs:
• 2-7;
• and
• (ii) a polynucleotide comprising a nucleic acid sequence with at least 80% identity to the nucleic acid sequence of any one of SEQ ID NOs:
• 2-7 which encodes the polypeptide of SEQ ID NO:8 and has equivalent or greater expression in a host relative to expression of any one of SEQ ID NOs:
• 2-7 or SEQ ID NO:1, wherein the polynucleotide does not have the nucleic acid sequence of SEQ ID NO:
• 1;
• and
• (b) any one or more of the following features:
• (i) a 3′ inverted terminal repeat (3′ ITR) with a length greater than 135 base pairs (bp) and less than 145 bp;
• (ii) fewer CpG dinucleotides as compared to a nucleic acid sequence of any one or more of SEQ ID NOs:
• 9-12 and 35-40;
• and
• (iii) fewer restriction enzyme recognition sites as compared to a nucleic acid sequence of any one or more of SEQ ID NOs:
• 9-12 and 35-40.