Heterogeneity of Marinesco-Sjögren syndrome: report of two cases

Marinesco-Sjögren syndrome is an autosomal recessive, multiorgan disorder with cardinal features of cerebellar ataxia, congenital or early childhood cataracts, psychomotor retardation, myopathy, and short stature. Mutations in the SIL1 gene on chromosome 5q31 were demonstrated to cause Marinesco-Sjögren syndrome. We describe two Turkish patients with clinical characteristics of Marinesco-Sjögren syndrome, but without mutations in SIL1. These two patients also manifested cerebral white matter involvement in cranial imaging, which was previously described in Marinesco-Sjögren syndrome. Marinesco-Sjögren syndrome is genetically heterogeneous, and mutations of SIL1 are often not evident. Consequently, we presume that new genes for Marinesco-Sjögren syndrome await discovery. New genes hold the promise of furthering the mechanistic understanding of the condition, enabling clinically meaningful genetic classification schemes to be designed.