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Background: Late infantile metachromatic leukodystrophy (MLD) is an autosomal recessive lysosomal storage disorder that causes severe demyelination of the nervous system. The neuronal metabolite N-acetylaspartate (NAA) serves as a source of acetyl groups for myelin lipid synthesis in oligodendrocytes and is known as a marker for neuronal and axonal loss. NAA and other metabolite levels measured by proton magnetic resonance spectroscopy (MRS) correlate with performance of the brain in normal children. There is a need for sensitive measures of disease progression in patients with MLD to enable development of future treatments., Methods: A cross-section of 13 children with late infantile MLD were examined by proton MRS. Signals from NAA, total choline, and total creatine in the deep white matter were measured and correlated with the results of cognitive and motor function tests., Results: The NAA signal decreased as the disease process advanced. Motor function, measured by the Gross Motor Function Measure-88, varied from 13 (only head movement in the supine position) to 180 (able to walk) across the study cohort, demonstrating a wide range in functional status. Similarly, varied decreases were observed in cognitive function. We report strong positive correlations between standardized measures of motor and cognitive function and NAA levels in the deep white matter., Conclusions: We suggest that NAA levels could serve as a sensitive biomarker in children with MLD. Proton MRS may provide a valuable tool for measuring the effects of treatment interventions in this disorder.

The spatial distribution of metabolite signal intensities can be measured within entire sections of the brain by proton magnetic resonance spectroscopic imaging (1H-MRSI). A group of six patients (4 unrelated girls and 2 brothers from 5 families) with childhood ataxia with diffuse CNS hypomyelination (CACH) underwent long-echo-time, single-slice 1H-MRSI. Relative to controls, there was a decrease in the signal intensity of N-acetylaspartate, choline, and creatine throughout the white matter in all six patients. We identified lactate signals in white matter in three of them with advanced disease. The degree of white matter involvement was not homogeneous over the entire patient group, but did correlate with clinical presentation. Deep and posterior white matter tended to be more involved. There were no 1H-MRSI abnormalities in the gray matter. 1H-MRSI findings suggest that this syndrome is secondary to a metabolic defect causing hypomyelination, axonal degeneration, and, in the most compromised cases, accumulation of lactate. This study shows that CACH is not limited to girls.

Vertebra plana and multiple platyspondyly are complications of aggressive Gaucher disease. Magnetic resonance imaging readily identifies vertebra plana and secondary spinal cord compression. We present a case of a 2-year-old boy with clinically aggressive Type 1 Gaucher disease in whom MRI showed partial reconstitution of the height of a collapsed lumbar vertebral body after 16 months of enzyme replacement therapy.

Elective subtotal splenectomy was performed in 33 patients (30 children and 3 adults) between 1981 and 1989. Indications for the procedure were (1) prevention of azathioprine-induced neutropenia (n = 20); (2) Type I Gaucher disease (n = 9); and (3) cholesteryl ester storage disease, chronic myelogenous leukemia, thalassemia major, and splenic cyst in one patient each. There were no operative deaths, no reoperations for bleeding, and 30 of 33 (91%) patients had a functioning splenic remnant documented by a postoperative radionuclide spleen scan. One patient developed neutropenia without evidence of viral infection that required temporary cessation of azathioprine and the patient with thalassemia major had only transient improvement in transfusion requirements. All other patients (94%) had control of the underlying condition for which the operation was performed. We conclude that subtotal splenectomy is a safe, effective therapy for a variety of nontraumatic conditions.