With the expansion of newborn screening in the past decade, biochemical variants are being uncovered without a clear understanding of their clinical significance. One such disorder is Short-chain acyl-CoA dehydrogenase (SCAD) deficiency, which causes an inability to process the shortest chain fatty acids. While early descriptions of this biochemical abnormality imply this is a disorder of real clinical effects, this may be due to an ascertainment bias since biochemical testing was sent in patients who already had clinical abnormalities (the SCAD deficiency might have been an incidental finding). van Maldegem et al. in Neuropediatrics. 2011 Feb;42(1):13-7 call into question the clinical significance of this disorder. I myself am hesitant to completely dismiss SCADD as completely clinically irrelevant until more data is available about long term follow ups of affected patients. However, I do admit to feeling conflicted about labeling my patients with a “disease” with so many unknowns about the clinical relevance of this disorder.
Hilary Vernon MD PhD