Supplementary Material for: Moderate Hyperhomocysteinemia along with Increased Levels of Vitamin B12 in a 21-Year-Old Male with the Sanfilippo Syndrome: A Case Report

The Sanfilippo syndrome is an autosomal recessive mucopolysaccharidosis. Homocysteine and B12 status have not been described in this syndrome. A 21-year-old bedridden male with the Sanfilippo syndrome was hospitalized. He was in poor nutritional status according to laboratory and somatometric findings, he had an enlarged liver, moderate aortic valve insufficiency and was under antiepileptic, antipsychotic and anti-cholinergic therapy. The patient had moderate hyperhomocysteinemia (16.9 μmol/L) with co-existing high levels of serum B12 (1,765 pg/mL). In addition, cystathionine, methionine sulphoxide and certain amino acids were measured. It was hypothesized that a “functional” deficiency of vitamin B12 may be due to problematic transcobalamin-vitamin B12 complex dissociation. Moreover, the patient’s cardiovascular background and/or medical treatment may explain the observed hyperhomocysteinemia. B12 and homocysteine status should be assessed in Sanfilippo patients. This report suggests that checking vitamin B12 and homocysteine status may be useful in the Sanfilippo syndrome.