Clinical Description
Marinesco-Sjögren syndrome (MSS) is characterized by cerebellar ataxia, dysarthria, nystagmus, early-onset cataracts, hypotonia, and muscle weakness. Additional features may include psychomotor delay, hypergonadotropic hypogonadism, short stature, and skeletal abnormalities. To date, at least 140 individuals have been identified with biallelic pathogenic variants in SIL1 [Anttonen et al 2005, Senderek et al 2005, Karim et al 2006, Annesi et al 2007, Anttonen et al 2008, Eriguchi et al 2008, Riazuddin et al 2009, Takahata et al 2010, Terracciano et al 2012, Krieger et al 2013, Ezgu et al 2014, Goto et al 2014, Inaguma et al 2014, Cerami et al 2015, Noreau et al 2015, Gai et al 2016, Nair et al 2016, Bayram et al 2022, Rochdi et al 2022, Faheem et al 2024]. The following description of the phenotypic features associated with this condition is based on these reports.
Table 2.
Marinesco-Sjögren Syndrome: Frequency of Select Features
View in own window
Feature | % of Persons w/Feature | Comment |
---|
Cerebellar ataxia
| >90% | |
Cerebellar atrophy
| 100% | |
Hypotonia
| 95%-100% | |
Cataracts
| 95%-100% | |
Intellectual disability
| >90% | Mild to severe |
Myopathic changes
| >90% | On EMG or muscle biopsy |
Strabismus
| 60%-80% | |
Hypergonadotropic hypogonadism
| 50%-70% | |
Short stature
| 50%-70% | |
Nystagmus
| ~50% | |
Orthopedic manifestations
| ~50% | Scoliosis; shortening of the metacarpals, metatarsals, & phalanges; coxa valga; pes planovalgus; & pectus carinatum |
Neuromuscular manifestations. Muscular hypotonia is usually present in early infancy resulting in motor delays. Distal and proximal muscular weakness is noticed during the first decade of life. Many affected individuals are never able to walk without assistance. Fine motor delays may also be present. Later, cerebellar findings of truncal ataxia, dysdiadochokinesia, nystagmus, and dysarthria become apparent. Motor function worsens progressively for some years, then stabilizes at an unpredictable age and degree of severity.
Ocular manifestations. Bilateral cataracts are not necessarily congenital and can develop rapidly. The mean age at onset of cataracts is approximately 3.5 years [Krieger et al 2013, Goto et al 2014]. Cataracts typically require lens extraction in the first decade of life. Strabismus is present in at least half of individuals reported [Goto et al 2014].
Intellectual abilities vary from normal to severe intellectual disability.
Endocrine. Hypergonadotropic hypogonadism and delayed puberty are frequent findings [Anttonen et al 2005, Anttonen et al 2008, Krieger et al 2013], but no associated congenital genital anomalies have been described.
Growth. Many individuals with MSS have short stature [Anttonen et al 2005, Anttonen et al 2008]. Microcephaly has occasionally been reported [Krieger et al 2013].
Skeletal findings. A variable degree of scoliosis is common. Additional typical clinical and radiographic skeletal findings include shortening of the metacarpals, metatarsals, and phalanges; coxa valga; pes planovalgus; and pectus carinatum [Reinker et al 2002, Mahjneh et al 2006]. The severity of the skeletal findings appears to correlate with the overall severity of other clinical manifestations [Mahjneh et al 2006].
Life span. Although many adults have severe disabilities, the life span associated with MSS appears to be near normal.