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X-Linked Intellectual Disability Type Snyder



  • He has been the Editor in Chief, JAMA Neurology (1997- present) and a member of the Editorial Board of JAMA (1997-present).[books.google.com]
  • [from OMIM:309583 ; 2018.02.26] Developmental delay usually presents as failure to meet early developmental milestones and then evolves to moderate to profound global intellectual disability (which appears to remain stable over time) and variable motor[flybase.org]
  • :3063 Synonym(s): Snyder-Robinson syndrome Prevalence: Inheritance: X-linked recessive Age of onset: Adolescent , Childhood , Infancy ICD-10: Q87.8 OMIM: 309583 UMLS: C0796160 MeSH: - GARD: 5615 MedDRA: - The documents contained in this web site are presented[orpha.net]
  • Developmental delay usually presents as failure to meet milestones and then evolves to moderate to profound global intellectual disability.[ncbi.nlm.nih.gov]
Short Stature
  • The affected males available for evaluation had mild ID, speech and global delay, an asthenic build, short stature with long fingers and mild kyphosis.[ncbi.nlm.nih.gov]
  • stature, pectus carinatum, and myopia that has_material_basis_in mutation in the SMS gene on chromosome Xp22.[informatics.jax.org]
  • stature, pectus carinatum, and myopia (summary by Zhang et al., 2013; pubmed:23696453 ).[flybase.org]
Tall Stature
  • stature Increased body height 0000098 Thick lower lip vermilion Increased volume of lower lip Plump lower lip Prominent lower lip [ more ] 0000179 Webbed neck Neck webbing 0000465 Wide intermamillary distance Wide-spaced nipples Widely spaced nipples[rarediseases.info.nih.gov]
  • Tall stature MedGen UID: 69137 • Concept ID: C0241240 • Finding A height above that which is expected according to age and gender norms.[ncbi.nlm.nih.gov]
  • stature Aganglionic megacolon Intellectual disability, profound Camptodactyly of finger Protruding ear Joint laxity Thin upper lip vermilion Fine hair Broad-based gait Narrow palate Disproportionate tall stature Slender finger Pyloric stenosis Microcornea[mendelian.co]
  • stature may suggest fragile X syndrome (FraX), Soto syndrome, or some other overgrowth syndrome associated with MR/ID Neurologic: This examination should include assessments of head growth (for microcephaly/macrocephaly), muscle tone (for hypotonia or[emedicine.medscape.com]
Difficulty Walking
  • People with this condition often have difficulty walking; most have an unsteady gait. Snyder-Robinson syndrome causes skeletal problems, particularly thinning of the bones ( osteoporosis ) that starts in early childhood.[ghr.nlm.nih.gov]
  • Low muscle tone ( hypotonia ) and muscle mass leads to difficulty walking and an unsteady gait.[rarediseases.info.nih.gov]
  • People with this condition often have difficulty walking; most have an unsteady gait.Snyder-Robinson syndrome causes skeletal problems, particularly thinning of the bones (osteoporosis) that starts in early childhood.[ncbi.nlm.nih.gov]
Nasal Voice
  • voice 0001611 Osteoporosis 0000939 Pectus carinatum Pigeon chest 0000768 Pectus excavatum Funnel chest 0000767 Recurrent fractures Increased fracture rate Increased fractures Multiple fractures Multiple spontaneous fractures Varying degree of multiple[rarediseases.info.nih.gov]
  • Following a perinatal intraventricular hemorrhage associated with thrombocytopenia (7 10 3 cells/μl) that corrected after 3 platelet transfusions, he developed seizures, apnea with cyanosis, temperature instability and hypoglycemia.[ojrd.biomedcentral.com]
Muscle Hypotonia
  • SRS results from a mutation in SMS and produces a complex multi-systemic phenotype including intellectual disability, dysmorphic facies, muscle hypotonia, kyphoscoliosis, osteoporosis, seizures, and speech and gait abnormalities.[ashg.org]
Decrease in Height
  • […] body height Small stature [ more ] 0004322 Talipes equinovarus Club feet Club foot Clubfeet Clubfoot [ more ] 0001762 Tall stature Increased body height 0000098 Thick lower lip vermilion Increased volume of lower lip Plump lower lip Prominent lower lip[rarediseases.info.nih.gov]
Normal Stature
  • In contrast to individuals with SRS, they have an excessively friendly mood, normal stature, and normal facial features [ Klitten et al 2011 ]. Glycerol kinase deficiency.[ncbi.nlm.nih.gov]
Widely Spaced Nipples
  • nipples Widely spaced nipples Widely-spaced nipples [ more ] 0006610 X-linked recessive inheritance 0001419 Showing of 36 Last updated: 5/1/2019 Making a diagnosis for a genetic or rare disease can often be challenging.[rarediseases.info.nih.gov]
Renal Stone
  • His renal stones were composed of carbonate apatite and calcium oxalate. His RTA has been managed with fluid and electrolyte replacement, spironolactone and hydrochlorothiazide.[ojrd.biomedcentral.com]


  • […] the following: Bayley Scales of Infant Development Stanford-Binet Intelligence Scale Wechsler Preschool and Primary Scale of Intelligence-Revised (WPPSI-R) Wechsler Intelligence Scale for Children–IV (WISC-IV) Vineland Adaptive Behavior Scales-II See Workup[emedicine.medscape.com]


  • These studies form a basis for further investigations into the leading biochemical changes and properties of SMS -mutant cells that potentially represent therapeutic targets for the treatment of Snyder-Robinson Syndrome.[preprints.org]
  • The material is in no way intended to replace professional medical care by a qualified specialist and should not be used as a basis for diagnosis or treatment.[orpha.net]
  • You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.[rarediseases.info.nih.gov]


  • PMID: 21219895 Prognosis Li C, Brazill JM, Liu S, Bello C, Zhu Y, Morimoto M, Cascio L, Pauly R, Diaz-Perez Z, Malicdan MCV, Wang H, Boccuto L, Schwartz CE, Gahl WA, Boerkoel CF, Zhai RG Nat Commun 2017 Nov 2;8(1):1257. doi: 10.1038/s41467-017-01289-7[ncbi.nlm.nih.gov]
  • Affected individuals should talk to their physician and medical team about their specific case, associated symptoms and overall prognosis.[rarediseases.org]
  • Genetic counselling aims to educate families about the syndrome, its implications and prognosis, supporting them in making informed decisions about the future and in dealing with the emotional impact of the diagnosis.[intellectualdisability.info]


  • We discuss this as well as our ongoing studies on the possible biochemical etiology for SRS. You may contact the first author (during and after the meeting) at[ashg.org]
  • Etiology Neurogenetics 2009 Oct;10(4):299-305. Epub 2009 Mar 7 doi: 10.1007/s10048-009-0184-2.[ncbi.nlm.nih.gov]
  • A genetic etiology is reported to account for as many as 60% of cases (McLaren and Bryson. 1987. PubMed ID: 3322329; Kaufman et al. 2010. PubMed ID: 21124998; Fieremans et al. 2016. PubMed ID: 27159028).[preventiongenetics.com]


  • Relevant External Links for SMS Human Genome Epidemiology (HuGE) Navigator SMS Atlas of Genetics and Cytogenetics in Oncology and Haematology: SMS No data available for Genatlas for SMS Gene X-linked spermine synthase gene (SMS) defect: the first polyamine[genecards.org]
  • Mental Subnormality in the Community: A Clinical and Epidemiologic Study. Baltimore: Williams & Wilkins; 1970. Strauss D, Eyman RK. Mortality of people with mental retardation in California with and without Down syndrome, 1986-1991.[emedicine.medscape.com]
  • Epidemiology There are about 100–200 affected births in the UK each year. The population prevalence is estimated at 1 in 4000 males and 1 in 8000 females (Hagerman and Hagerman, 2002). It occurs in all races and ethnic groups.[intellectualdisability.info]
Sex distribution
Age distribution


  • Pathophysiology MR/ID is the end result of many disorders of CNS function. Most individuals with significant intellectual impairment have no discernible structural abnormalities of the brain.[emedicine.medscape.com]


  • The loss of activity was attributed to the increase in conformational dynamics in the mutant which affects the active site geometry, rather than preventing dimer formation.[ncbi.nlm.nih.gov]
  • The loss of activity was attributed to the increase of conformational dynamics in the mutant which affects the active site geometry, rather than preventing dimer formation.[lirias.kuleuven.be]
  • This DNA vaccine has the potential to be a safe and effective therapy to prevent Alzheimer disease. He described Machado-Joseph disease (MJD), an autosomal dominant ataxia, with William Nyhan, M.D. Ph.D, in 1976, for the first time.[books.google.com]
  • And are not intended to diagnose, treat, cure or prevent disease. The information presented is not intended to replace medical advice or treatment from your own doctor or healthcare provider.[wellnessadvocate.com]
  • The early years are of vital importance for stimulating maximum learning in children with the syndrome, and intervention at this stage can prevent many problems later.[intellectualdisability.info]

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