The syndrome causes cerebellar ataxia (balance and coordination problems), intellectual disability, congenital cataracts in early childhood, muscle weakness, inability to chew food, thin brittle fingernails, and sparse hair.

[1]: 578 Small stature, mild to severe intellectual disability and dysarthria (slow, imprecise speech) are usually present.

[2][3] SIL1 gene is located on chromosome 5q31.2[4] Diagnosis of MSS is based on clinical symptoms, magnetic resonance imaging (MRI) of the brain (cerebellar atrophy particularly involving the cerebellar vermis), and muscle biopsy.

[citation needed] Marinesco–Sjögren-like syndrome is a very rare genetic disorder which is characterized by symptoms similar to those shown by people with Marinesco–Sjögren syndrome, the symptoms (of this variant of MSS) being infantile hypotonia, ataxia, cataracts, intellectual disabilities, cerebellar atrophy, myopathic alterations, vascular degeneration, and adipose tissue proliferation.

[citation needed] Members of the MOWA Band of Choctaw Indians, a state-recognized tribe located in southwest Alabama, have a high frequency of Marinesco–Sjögren syndrome and have been the subject of study.