Short chain acyl-CoA dehydrogenase deficiency (SCADD)

The beta-oxidation of fatty acids is an essential metabolic process for obtaining acetyl-CoA, a molecule from which the mitochondria of cells obtain energy from fats.

Short-chain acyl-CoA dehydrogenase deficiency or SCADD is a disorder that affects beta-oxidation by altering the acyl-CoA dehydrogenase enzyme involved in this metabolic pathway, resulting in the accumulation of the metabolites butyrylcarnitine and ethylmalonic acid.

In the United States, most infants with SCADD are identified through neonatal screening programs. Most patients are usually asymptomatic so it is now considered more of a biochemical feature than a pathology. On the other hand, in countries where SCADD is not part of such programs, children and adults with SCADD are identified if they show clinical symptoms by biochemical assessment of SCADD levels.In those countries where SCADD is not part of such programs, children and adults with SCADD are identified if they show clinical symptoms by biochemical assessment of urinary ethylmalonic acid or EMA and butyrylglycine levels, plasma butyrylcarnitine and acyl-CoA dehydrogenase enzyme activity in skin or muscle fibroblasts.

As with other fatty acid oxidation deficits, the biochemical-level alterations characteristic of SCADD are usually absent in individuals with SCADD, except at times of physiological stress such as fasting and illness.

Exceptionally occurring symptoms include dysmorphic facial features, developmental delay, feeding difficulties, metabolic acidosis, epilepsy, ketotic hypoglycemia, developmental delay, lethargy, seizures, dystonia, myopathy, and hypotonia.

There are no global recommendations for the management of people with SCADD with and without symptoms due to the absence of long-term follow-up studies.

If necessary, it is suggested as a preventive measure to avoid fasting, since in some people affected by SCADD it can lead to dehydration, metabolic acidosis and hypoglycemia.