CT and MR studies of methylmalonic acidemia.
نویسندگان
چکیده
Methylmalonic acidemia (MMA) is a disorder of organic acid metabolism. It consists of a group of biochemically and genetically distinct disorders that produces a block in the conversion of methylmalonyi-CoA to succinyi-CoA, with consequent accumulation of methylmalonate in the blood and urine, secondary hyperammonemia, and often severe ketoacidosis [1]. Methylmalonic acid is part of the organic and amino acid oxidative process, in which the methylmalonyi-CoA is converted to succinyi-CoA by methylmalonylmutase, an enzyme whose cofactor is a cobalamin coenzyme (5 ' -deoxyadenosyl cobalamin). MMA is caused by absence or mutation of methylmalonylmutase or by defective synthesis of the coenzyme, and is transmitted in an autosomal recessive inheritance pattern [1]. Rarely, MMA can be produced by a deficit of the racemase that converts o-methylmalonyi-CoA to L-methylmalonyi-CoA [2]. In the affected patients, an increase of methylmalonic acid in blood produces marked ketoacidosis, lethargy, and coma [1 , 3-5]. The long-lasting metabolic disorder produces physical and mental delay. Aicardi [3] has reviewed the clinical and neuroradiologic features of MMA. CT demonstrates, even in the acute phase, areas of hypodensity affecting the pallidal nuclei bilaterally, which do not enhance after infusion of iodinated contrast medium, although enhancement can occur in the subacute phase [5]. In our case, immediately after the onset of the disease, MR showed the cytotoxic edema affecting the pallidal nuclei bilaterally, characterized by low signal intensity on T1-weighted images and high signal intensity on T2-weighted images. The neuroradiologic follow-up showed the progressive changes of necrosis in these lesions.
منابع مشابه
CT and MR of the brain in disorders of the propionate and methylmalonate metabolism.
PURPOSE To present the CT and MR findings in children with propionic and methylmalonic acidemia. METHODS Twenty-three new patients with methylmalonic and 20 with propionic acidemia were examined with CT and/or MR of the brain. In total 52 CT and 55 MR studies were done. Twenty-six previously published cases were also reviewed. RESULTS The findings were similar in the two syndromes. During t...
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ورودعنوان ژورنال:
- AJNR. American journal of neuroradiology
دوره 12 3 شماره
صفحات -
تاریخ انتشار 1991