Sulfites Abstracts 4

© 2012

Clinical and imaging observations in isolated sulfite oxidase deficiency

         (Bindu, Christopher et al. 2011) Download

Isolated sulfite oxidase deficiency is a rare neurometabolic disorder that closely mimics hypoxic ischemic encephalopathy both clinically and radiologically. Phenotypic and imaging observations in 2 children (aged 14 months and 8 years) with this disease are described. Both had profound mental retardation, microcephaly, spastic quadriparesis, and uncontrolled seizures from the neonatal period. Diagnosis was established by demonstrating the presence of sulfites in urine and genetic analysis. Magnetic resonance imaging of the brain revealed severe cystic leukomalacia, cortical atrophy with ulegyric pattern, and cerebellar hypoplasia that progressed over time in both the patients. Early diagnosis of this devastating disorder will provide an opportunity for genetic counseling and prenatal testing.

Isolated sulphite oxidase deficiency mimics the features of hypoxic ischaemic encephalopathy

            (Hobson, Thomas et al. 2005) Download

Isolated sulphite oxidase deficiency (ISOD) is a rare autosomal recessive inborn error of metabolism, which may present at birth with intractable seizures (often of prenatal onset) and severe neurological abnormalities. In infants who survive, lens dislocation may occur from 8 weeks of age. The neuropathological findings in ISOD are similar to those seen in severe perinatal asphyxia. We describe two siblings with ISOD born to healthy non-consanguineous parents. The first child presented within 48 h of birth with poor feeding and seizures. He died from septicaemia on day 20 of life. The clinical presentation, neuroradiology and autopsy suggested a diagnosis of severe hypoxic ischaemic encephalopathy with a low recurrence risk. The second child presented with seizures within an hour of birth. She lived for 16 months during which time she failed to make developmental progress and continued to experience intractable seizures. Her neuroradiology was similar to her brother's. A diagnosis of ISOD was suggested from high urinary S-sulphocysteine in the second child and confirmed by the absence of sulphite oxidase activity in skin fibroblast culture. The diagnosis has enabled the couple to access prenatal testing in a subsequent pregnancy. CONCLUSION: Isolated sulphite oxidase deficiency is an autosomal recessive condition which may mimic ischaemic encephalophathy. The disorder should be considered in all cases of intrauterine seizures, intractable seizures in the newborn period and infants with clinical and radiological features of ischaemic encephalophathy, especially when no obvious insult can be determined.

Effect of sulfite on cognitive function in normal and sulfite oxidase deficient rats

            (Kucukatay, Savcioglu et al. 2005) Download

Sulfites, which are commonly used as preservatives, are continuously formed in the body during metabolism of sulfur-containing amino acids. Sulfite is oxidized to sulfate ion by sulfite oxidase (SOX, EC. 1.8.3.1). The aim of this study was to investigate the possible toxic effects of sulfite on neurons by measuring active avoidance learning in normal and SOX-deficient rats. For this purpose, male albino rats used in this study were divided into eight groups such as control group (C), sulfite group (25 mg/kg) (S), vitamin E group (50 mg/kg) (E), sulfite (25 mg/kg)+vitamin E group (50 mg/kg) (SE), SOX-deficient group (D), deficient+vitamin E group (50 mg/kg) (DE), deficient+sulfite group (25 mg/kg) (DS) and deficient+sulfite (25 mg/kg)+vitamin E group (50 mg/kg) (DSE). Sulfite-induced impairment of active avoidance learning in SOX-deficient rats but not in normal rats. Sulfite had no effect on hippocampus TBARS levels in SOX normal groups. In SOX-deficient rats, TBARS levels were found to be significantly increased with sulfite exposure. Vitamin E reversed the observed detrimental effects of sulfite in the SOX-deficient rats on their hippocampal TBARS but not on their active avoidance learning. In conclusion, sulfite has neurotoxic effects in sulfite oxidase deficient rats, but this effect may not depend on oxidative stress.

Urinary AASA excretion is elevated in patients with molybdenum cofactor deficiency and isolated sulphite oxidase deficiency

            (Mills, Footitt et al. 2012) Download

Analysis of alpha-aminoadipic semialdehyde is an important tool in the diagnosis of antiquitin deficiency (pyridoxine-dependent epilepsy). However continuing use of this test has revealed that elevated urinary excretion of alpha-aminoadipic semialdehyde is not only found in patients with pyridoxine-dependent epilepsy but is also seen in patients with molybdenum cofactor deficiency and isolated sulphite oxidase deficiency. This should be taken into account when interpreting the laboratory data. Sulphite was shown to inhibit alpha-aminoadipic semialdehyde dehydrogenase in vitro.

Laboratory diagnosis of sulphite oxidase deficiency

            (Sass 2006) Download


References

Bindu, P. S., R. Christopher, et al. (2011). "Clinical and imaging observations in isolated sulfite oxidase deficiency." J Child Neurol 26(8): 1036-40.

Hobson, E. E., S. Thomas, et al. (2005). "Isolated sulphite oxidase deficiency mimics the features of hypoxic ischaemic encephalopathy." Eur J Pediatr 164(11): 655-9.

Kucukatay, V., F. Savcioglu, et al. (2005). "Effect of sulfite on cognitive function in normal and sulfite oxidase deficient rats." Neurotoxicol Teratol 27(1): 47-54.

Mills, P. B., E. J. Footitt, et al. (2012). "Urinary AASA excretion is elevated in patients with molybdenum cofactor deficiency and isolated sulphite oxidase deficiency." J Inherit Metab Dis.

Sass, J. O. (2006). "Laboratory diagnosis of sulphite oxidase deficiency." Eur J Pediatr 165(10): 739; author reply 740.