CEREBELLAR INVOLVEMENT IN METABOLIC DISORDERS - A PATTERN-RECOGNITIONAPPROACH

Inborn errors of metabolism can affect the cerebellum during developme nt, maturation and later during life. We have established criteria for pattern recognition of cerebellar abnormalities in metabolic disorder s. The abnormalities can be divided into four major groups: cerebellar hypoplasia (CH), hyperplasia, cerebellar atrophy (CA), cerebellar whi te matter abnormalities (WMA) or swelling, and involvement of the dent ate nuclei (DN) or cerebellar cortex. CH can be an isolated typical fi nding, as in adenylsuccinase deficiency, but is also occasionally seen in many other disorders. Differentiation from CH and CA is often diff icult, as in carbohydrate deficient glycoprotein syndrome or 2-L-hydro xyglutaric acidaemia. In cases of atrophy the relationship of cerebell ar to cerebral atrophy is important. WMA may be diffuse or patchy, fre quently predominantly around the DN. Severe swelling of white matter i s present during metabolic crisis in maple syrup urine disease. The DN can be affected by metabolite deposition, necrosis, calcification or demyelination. Involvement of cerebellar cortex is seen in infantile n euroaxonal dystrophy. Changes in DN and cerebellar cortex are rather t ypical and therefore most helpful; additional features should be sough t as they are useful in narrowing down the differential diagnosis.