In vivo brain proton MR spectroscopy in a case of molybdenum cofactor deficiency

Molybdenum cofactor deficiency: Neuroimaging findings

Molybdenum cofactor deficiency is an extremely rare and fatal metabolic disorder that should be considered in the differential diagnosis of hypoxic-ischemic encephalopathy. Magnetic resonance imaging findings are useful in diagnosis. The short-echo-time magnetic resonance spectrum was characterized by a total loss of signal and lipid and lactate peaks. In this case, conventional magnetic resonance imaging and magnetic resonance spectroscopy findings of this extremely rare disease whose pathophysiology was not known were presented.

Proton magnetic resonance spectroscopy and diffusion-weighted imaging in isolated sulfite oxidase deficiency

Isolated sulfite oxidase deficiency is a rare autosomal recessive disorder of the newborn that can be mistaken for neonatal asphyxia. Diffusion-weighted imaging of the brain demonstrates widespread diffusion restriction, and proton magnetic resonance spectroscopy shows an elevated lactate level, a decrease in the ratio of N-acetylaspartate to creatine, and a rise in the ratio of choline to creatine. This precedes severe cystic encephalomalacia and suggests that the energy failure associated with neuronal dysfunction and myelin disintegration occurs early in isolated sulfite oxidase deficiency.

Molybdenum cofactor deficiency presenting with severe metabolic acidosis and intracranial hemorrhage

Molybdenum cofactor deficiency leads to combined deficiency of sulfite oxidase, xanthine dehydrogenase, and aldehyde oxidase enzyme activities. The major clinic symptom is intractable seizures seen soon after birth. No definite therapy is available. We report here a newborn with molybdenum cofactor deficiency-associated Dandy-Walker malformation who presented with severe lactic acidosis and intracranial hemorrhage.

Metabolites in ventricular cerebrospinal fluid detected by proton magnetic resonance spectroscopic imaging

Normally, ventricular cerebrospinal fluid (CSF) contains low levels of all metabolite signals on proton magnetic resonance spectroscopic imaging (MRSI). We present here three cases (two with seizure disorders, one with a central nervous system lymphoma) who presented with unusually elevated CSF signals on MRSI. Based on chemical shifts and in vitro studies (in one case), the signals were assigned to propan-1,2-diol (PD), acetone, and lactate, respectively. These compounds were either exclusively, or more readily, detected in CSF than in brain. Proton MRSI conveniently screens both brain and CSF for abnormal metabolism simultaneously.

New insights into the neuropathogenesis of molybdenum cofactor deficiency

BACKGROUND

Molybdenum cofactor deficiency (MOCOD) is a rare, progressive neurodegenerative disorder caused by sulphite oxidase enzyme deficiency. The neuropathological findings are consistent with a toxic insult to the brain that causes severe neuronal loss, reactive astrogliosis and spongiosis. The mechanisms responsible for these changes are unknown.

METHODS

The case is a male infant with MOCOD who died at nine months of age from pneumonia. At autopsy, a complete neuropathological examination was performed including conventional immunohistochemical staining. In addition, brain sections were stained cytochemically with shikata and orcein which stain for disulphide bonds. The elemental composition of cortical cells was then analyzed in the scanning electron microscope using backscatter electron imaging and energy dispersive X-ray spectrometry.

RESULTS

Neurons demonstrated cytoplasmic staining with shikata and orcein cytochemically when compared to control sections. Energy dispersive X-ray spectrometry analysis of these neurons confirmed the presence of excess sulphur and unexpectedly revealed excess magnesium accumulation. None of these findings was found in an age-matched control.

CONCLUSIONS

In MOCOD we found abnormal accumulation of sulphur and magnesium in neurons. It is postulated that sulphur-containing compound(s) that are formed as a result of MOCOD cause excitotoxic neuronal injury in the presence of excess magnesium.