Similarly, a Galician study [30], which analyzed 440.723 newborns screened over 22 years, found that in 4% (n = 13) of patients, clinical signs of metabolic intoxication emerged before ENS results were available (at a median age of 3 days), including cases of citrullinemia type 1 (CIT1), maple syrup urine disease (MSUD), propionic acidemia (PA), methylmalonic acidemia (MMA), and carnitine-acylcarnitine translocase deficiency (CACTD). Here, SLC25A20 is linked to methylmalonic acidemia.