DWQA QuestionsCategory: QuestionsI have adult onset SCADD with severe neuro symptoms. I have been told to supplement Coq10 but cannot tolerate it. Do you have any experience with why this may happen?
Paige Hadley asked 4 weeks ago
I have adult onset symptomatic SCADD. Confirmed by high urinary ethylmalonic and methylsuccinic acid, along with elevated acyl carnitines, as well as a rare pathogenic ACADS variant. I tried to make an apointment with Dr. Vockley but unfortunately was told it was not possible, so I am trying to look for guidance elsewhere, while my condition declines.

A neurologist diagnosed me, and I saw great improvement with riboflavin supplementation. I did not have a complete resolution of symptoms, and eventually, after increasing the dose too high, my symptoms all returned along with new, cardiovascular symptoms and a very strange, sulfuric odor in urine resembling a pack of matches. I am a 30 year old female. Recently my doctor discussed the possibility of synergistic heterozygosity and suggested maybe hydrogen sulifde could be backing up my short chain fat oxidation. I tried coq10 at his suggestion in low doses, and had nearly instant flushing and heart palpitations. He suggested a possible “block” in complex III causing this issue, which was later confirmed by a mitoswab test showing low complex III function. Is this a phenomena you see sometimes? As far as im aware, coq10 metabolizes sulfur into sulfite, which then must go throufh glutathione and a molybdenum dependent enzyme before being broken down into sulfate. I hypothesized that I may be experiencing this flushing because if inadequate molybdenum status (which is impossible to test as far as I’m aware) causing a reaction to a sudden increase in sulfite. My doctor says this makes sense, but can only guess and is not a FAOD expert. I wondered if this is an issue you have seen before.

Thank you for your time.

1 Answers
Keith McIntire answered 4 weeks ago


When SCAD deficiency was first discovered, it became associated with a large spectrum of symptoms. It wasn’t until much later that investigators realized that nearly all of those patients didn’t really have SCAD deficiency, but rather one of two very common variants in the gene that led to presence of some of the chemicals in blood and urine seen in complete deficiency, with slightly reduced enzyme activity, but enough to not really cause any clinical symptoms. Subsequently, it was shown that babies identified with complete SCAD deficiency by newborn screening were all well. Thus, SCAD deficiency is no longer categorized as a disease, but simply a chemical characteristic. There are actually quite a few of these identified in people. In your setting, the biochemical findings and your clinical symptoms are unlikely to have anything to do with what sounds like a single variant in the SCAD gene. Your clinical symptoms and other findings are too complicated for me to comment on except to say that you should see a metabolic specialist who can evaluate you further. There are functional tests that might be useful to further diagnose your condition as well as possibly exome or genome sequencing.

I hope this helps. Dr. Vockley