ETFDH and multiple acyl-CoA dehydrogenase deficiency: Indeed, late-onset MADD represents the milder form of a severe genetic metabolic disorder, and, in agreement, it is associated with a partial deficiency of the ETFDH enzyme activity, as in Case 4, who was homozygous for the c.1286-15T > A intronic variant that strongly reduced, but did not abolish, the normal RNA splicing.