DWQA QuestionsCategory: QuestionsSecondary Carnitine Deficiency risk in MCADD Patient
Ryan Sampson asked 5 months ago
My daughter is 6 years old with MCADD. She was initially prescribed a carnitine supplement as a baby and has been off this supplementation for about a year. She’s had blood tests at roughly 6 month intervals showing low levels of carnitine but still within an acceptable range, so she’s remained off the supplement. Because of the low level though, her metabolic nurses have classified her as having mild secondary carnitine deficiency.
With this, I’m wondering about the risks I should watch out for with secondary carnitine deficiency. From what I understand:

Muscle fatigue, exercise intolerance, or muscle cramps. If this occurs, is the recommended treatment to have a carnitine supplement on hand?
Increased liver or heart size. How will I know if this is happening? Are there tests that I can request from our doctor? Any treatment recommendations?
Anything else?

I understand the evidence is limited and mixed on the benefits of carnitine supplementation. I’m just hoping to have a reasonable understanding of what to watch out for and what I might be able to do about it.

1 Answers
Keith McIntire answered 5 months ago
Thank you for your question. Nearly all patients with MCAD deficiency have low blood carnitine levels and current consensus is to not treat unless patients are symptomatic.
The reason is that most of the carnitine is actually in muscles and blood levels don’t accurately reflect muscle. Therefore, I don’t even check carnitine levels
unless symptoms are present, which is quite rare.  You should watch for exercise intolerance, fatigue, or muscle cramps. I hope this helps. Dr.Vockley