ABCB4 and hyperinsulinemic hypoglycemia, familial, 4: Some conditions such as congenital glycosylation disorders, MEDNIK syndrome, manganese transport defects, and multidrug resistance protein 3 (MDR3) deficiency [21] may strongly resemble WD in terms of low serum copper and/or ceruloplasmin levels, copper accumulation on liver biopsy, and increased copper excretion [22,47,92], but these conditions are not usually associated with an acute onset of disease.