PRIMARY DEGENERATION OF THE GRANULAR LAYER OF THE CEREBELLUM - A STUDY OF 14 PATIENTS AND REVIEW OF THE LITERATURE

Primary degeneration of the granular layer of the cerebellum is an aut osomal recessive disorder exhibiting characteristic clinical features: hypotonia, strabismus, delayed motor development, nonprogressive atax ia, delayed language development with dysarthria and mental retardatio n. We studied fourteen children, seven of each gender. Neuroimaging te sts including pneumoencephalogra phy, computed tomography (CT) and mag netic resonance imaging (MRI) showed severe cerebellar atrophy in all. MRI best demonstrated the cerebellar lesion, revealing great uniformi ty amongst the cases. Vertebrobasilar angiography was performed in two cases and showed marked hypoplasia of the cerebellar arteries, predom inantly the posterior inferior cerebellar artery (PICA) and its branch es. Necropsy was performed in three cases; cerebellar atrophy with los s of granular cells and diverse abnormalities of the Purkinje cells wa s found in two. The third, the sister of one of the other two cases, h ad a similar but shorter clinical course and died at three months of a ge. Her sister, who died at 5 years of age, presented a severe cerebel lar atrophy with typical changes in the granular cell layer and Purkin je cells. In the third patient, who lived three months, only focal cer ebellar folial atrophy with no microscopic changes in the granular cel l layers was present. Though this case cannot objectively be included in the cerebellar atrophy syndrome with granular cell loss, her family history and clinical picture suggest the same disease. The findings o bserved in our series and the study of cases described in the literatu re, suggest that there are several forms of this disease which differ mainly in severity and neurological evolution. The cerebellar lesion s eems to be a progressive atrophic process with the most severe changes during the early years of life.