PROTON MAGNETIC-RESONANCE SPECTROSCOPY IN AN ITALIAN FAMILY WITH SPINOCEREBELLAR ATAXIA TYPE-1

Linkage and DNA analysis, magnetic resonance (MR) imaging, and single- voxel proton MR spectroscopy were obtained in 10 members of an Italian kindred with spinocerebellar ataxia type 1 (SCA1). The size of the ba sis pontis, cerebellar hemispheres, middle cerebellar peduncles, and m edulla oblongata were decreased in 4 members carrying the SCA1 gene, c ompared with 6 unaffected subjects. Diffuse signal changes in the pens and cerebellum mere observed only in the carrier with the longest dis ease duration and greatest disability. The N-acetylaspartate/creatine ratio and the choline/creatine ratio in the basis pontis were markedly decreased in 2 symptomatic SCA1 carriers and moderately decreased in 2 asymptomatic SCA1 carriers, compared with the unaffected family memb ers and a control group of 10 healthy volunteers. Minor decreases in t he N-acetylaspartate/creatine ratio and the normal choline/creatine ra tio mere observed in the cerebellar hemisphere of the SCA1 carriers. R eduction of the N-acetylaspartate/creatine ratio, demonstrated by MR s pectroscopy in the pens, is likely to reflect a loss of neuronal viabi lity and might represent a biochemical marker of SCA1 more sensitive t han brainstem and cerebellum atrophy and signal changes shown by MR im aging.