Genetic testing revealed for all homozygosity for the common severe ACADM gene variant (c.985 A > G) found in about 80% of symptomatically diagnosed patients in the pre-screening era [14] and in about 32% to 59% of neonatally screened individuals with MCAD deficiency [5, 13]. This evidence concerns the gene ACADM and medium chain acyl-CoA dehydrogenase deficiency.