Early Genetic Diagnosis Of Marinesco–Sjögren Syndrome In An Infant Without Cataract: Expanding The Phenotypic Spectrum

Abstract

Background: Marinesco–Sjögren syndrome (MSS) is a rare autosomal recessive disorder, classically presenting with early-onset cataracts, cerebellar ataxia, and developmental delay. Case Presentation:  we present a one-year-old male child born to third degree consanguineous parents with global developmental delay and hypotonia. Neuroimaging showed cerebellar hypoplasia. In view of clinical suspicion of MSS, even though the child hasn’t developed cataract, whole-exome sequencing done which revealed homozygous frameshift mutation (c.302_303del) in exon 4 of the SIL1 gene. This case highlights that MSS may present before cataract onset, and early neuroimaging and genetic testing can clinch the diagnosis. Conclusion: MSS should be considered in infants with unexplained hypotonia and cerebellar hypoplasia, even in the absence of cataracts.