LBSL (leukoencephalopathy with brain stem and spinal cord involvement and high lactate) without sparing of the u-fibers and globi pallidi: A case report

Leukoencephalopathy with brain stem and spinal cord involvement and high lactate (LBSL) is a recently identified leukoencephalopathy, first described by Van der Knaap in 2003. To date 24 cases have been described. Distinctive features were as follows. First, brain MRI showed white matter abnormalities and involvement of brain stem structures. Second, sparing of the u-fibers was an invariant, distinctive feature of the syndrome. Third, whenever evaluated, spinal cord was always involved. Fourth, brain [1H]-MR spectroscopy failed to show a lactate peak in all cases. In our little child, the diagnosis was confirmed by genetic analysis but unlike previous report both the u-fibers and globus pallidus were involved; spectroscopic data were more consistent with hypomyelination than demyelination. Our findings add to the phenotype variability of this novel disease.