SIL1 and SARA2 mutations in Marinesco-Sjögren and chylomicron retention diseases.

Marinesco-Sjögren Syndrome (MSS) is an autosomal recessive disorder, characterized by cataracts, ataxia, and growth and mental retardation. Chronic myopathy is a common feature, and peripheral neuropathy has also been described. Recently, Lagier-Tourenne et al. (1) identified a candidate MSS locus on chromosome 5q31 by homozygosity mapping in two large consanguineous families with MSS. More recently, Anttonen et al. (2) confirmed the linkage of the MSS phenotype to 5q31 chromosome in a Finnish family, and identified a homozygous four-nucleotide duplication 506_509dupAAGA – in exon 6 of the SIL1 gene – in all investigated MSS patients. Senderek et al. (3), using homozygosity mapping in three small consanguineous families with typical MSS, narrowed a critical region on 5q31. In this region the authors identified nine distinct mutations in SIL1 gene in individuals from eight small families with MSS.