Snyder-Robinson syndrome, also known as spermine synthase deficiency, is an X-linked intellectual disability syndrome (OMIM #390583). First described by Drs. Snyder and Robinson in 1969, this syndrome is characterized by an asthenic body habitus, facial dysmorphism, broad-based gait, and osteoporosis with frequent fractures. We report here a pediatric autopsy of a 4 year old male with a history of intellectual disability, gait abnormalities, multiple fractures, and seizures previously diagnosed with Snyder-Robinson syndrome with an SMS gene mutation (c.831G>T:p.L277F). The cause of death was hypoxic-ischemic encephalopathy secondary to prolonged seizure activity. Although Snyder-Robinson syndrome is rare, the need to recognize clinical findings in order to trigger genetic testing has likely resulted in under diagnosis.
SnyderRD, RobinsonA. Recessive sex-linked mental retardation in the absence of other recognizable abnormalities: report of a family. Clin Pediatr (Phila). 1969;8(11):669-74. [https://doi.org/10.1177/000992286900801114]. [PMID:5823961]
CasonAL, IkeguchiY, SkinnerC, et al. X-linked spermine synthase gene (SMS) defect: the first polyamine deficiency syndrome. Eur J Hum Genet. 2003;11(12):937-44. [https://doi.org/10.1038/sj.ejhg.5201072]. [PMID:14508504]
AlbertJ, SchwartzCE, BoerkoelCF, StevensonRE. Snyder-Robinson syndrome. In: AdamMP, ArdingerHH, PagonRA, et al., editors. GeneReviews® [Internet]. Seattle: University of Washington; 2013 [cited 2013 Jun 27]. p. 1993-2018. Available from: https://www.ncbi.nlm.nih.gov/books/NBK144284/
AlencastroG, McCloskeyDE, KliemannSE, et al. New SMS mutation leads to a striking reduction in spermine synthase protein function and a severe form of Snyder-Robinson X-linked recessive mental retardation syndrome. J Med Genet. 2008;45(8):539-43. [https://doi.org/10.1136/jmg.2007.056713]. [PMID:18550699]
Becerra-SolanoLE, ButlerJ, Castaneda-CisnerosG, et al. A missense mutation, p.V132G, in the X-linked spermine synthase gene (SMS) causes Snyder-Robinson syndrome. Am J Med Genet. 2009;149A(3):328-35. [https://doi.org/10.1002/ajmg.a.32641]. [PMID:19206178]
ZhangZ, NorrisJ, KalscheuerV, et al. A Y328C missense mutation in spermine synthase causes a mild form of Snyder–Robinson syndrome. Hum Mol Genet. 2013;22(18):3789-97. [https://doi.org/10.1093/hmg/ddt229]. [PMID:23696453]
PeronA, SpacciniL, NorrisJ, et al. Snyder-Robinson syndrome: a novel nonsense mutation in spermine synthase and expansion of the phenotype. Am J Med Genet. 2013;161A(9):2316-20. [https://doi.org/10.1002/ajmg.a.36116]. [PMID:23897707]
AbelaL, SimmonsL, SteindlK, et al. N(8)-acetylspermidine as a potential plasma biomarker for Snyder-Robinson syndrome identified by clinical metabolomics. J Inherit Metab Dis. 2016;39(1):131-7. [https://doi.org/10.1007/s10545-015-9876-y]. [PMID:26174906]