Infantile Refsum disease (IRD) is a rare autosomal recessive[2] congenital peroxisomal biogenesis disorder within the Zellweger spectrum.

[6] In addition, patients can show a reduction in central nervous system (CNS) myelin (particularly cerebral), which is referred to as (hypomyelination).

[9] Infantile Refsum disease is an autosomal recessive disorder caused by mutations in genes that encode peroxins, proteins required for normal peroxisome assembly.

[1] In almost all cases, patients have mutations that inactivate or greatly reduce the activity of both the maternal and paternal copies of one of these aforementioned PEX genes.

In addition, these individuals can show deficient levels of plasmalogens, ether-phospholipids that are especially important for brain, lung, and heart functions.