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INTRODUCTION
Recently, leukoencephalopathies associated with hereditary disorders of myelin formation and metabolism became focus of the study of congenital causes of white-matter diseases. Among the non-classified leukoencephalopathies, the group hypomyelination diseases stands out as the largest category.

CASE REPORT
Female patient, 4 years old, presented motor and speech delay which was noticed after 18 months of life and evolved with movement disorder and loss of motor skills. It was observed dystonic posturing of limbs, asymmetric intent dystonia, head wobble and bilateral intention tremor of the upper limbs, those associated with global cerebellar ataxia. The patient had a brain magnetic resonance imaging (MRI), performed 7 months earlier, which demonstrated abnormalities of the periventricular and subcortical white matter - involving the U- fibers, with hyperintense signal on T2 and FLAIR and cerebellar atrophy. Another MRI performed in our service showed the same features, now with reduced volume in both of the the putamens. Imaging findings fulfill the criteria of hypomyelination, with the characteristic changes of HABC.

DISCUSSION
The first description of this entity was made in 2002 and, since then, the diagnosis is based on neuroimaging criteria . The clinical picture is heterogeneous, including developmental delay, ataxia and extrapyramidal signs. Greater severity was associated with a higher degree of atrophy of the basal ganglia, with description of complete disappearance of putamens. Recently been associated with de novo mutation of the β - tubulin gene, TUBB4A, which was related to congenital dystonia.

leukoencephalopathy, hypomyelination, white-matter disease, cerebellum, basal ganglia, dystonia