Recommended laboratory testing to follow children diagnosed with RCDP includes:

• Phytanic acid levels
• Level of docohexanoic acid or DHA
• Plasmalogen levels
• Routine liver function tests, complete blood count, basic chemistry panel, calcium, phosphorus, and Vitamin D levels

Phytanic acid levels could be high in children with RCDP type 1 (PEX7 defect) whose diet is not largely composed of an infant formula. If phytanic acid levels are very high, we recommend dietary changes to reduce these levels.

It is possible that DHA levels might also be low in children with all forms of RCDP, and since DHA can also be supplemented, we recommend that DHA levles be followed.

Plasmalogen levels are obtained at diagnosis however, it is unclear if these levels increase over time, possibly due to recycling of existing plasmalogens. In order to determine this, we suggest obtaining a repeat red blood cell plasmologen level every few years.

When you have this laboratory testing on your children, please be sure to include the physician involved in the care of the child to whom the results should be sent.