PEX26 and peroxisome biogenesis disorder: Biallelic mutations in the PEX1 (OMIM# 602136), PEX6 (OMIM# 601498), PEX10 (OMIM#602859), PEX12 (OMIM# 601758), or PEX26 (OMIM# 608666) genes are found in approximately 90% of ZSD patients.