x linked mental retardation

Summary

Summary: A class of genetic disorders resulting in INTELLECTUAL DISABILITY that is associated either with mutations of GENES located on the X CHROMOSOME or aberrations in the structure of the X chromosome (SEX CHROMOSOME ABERRATIONS).

Top Publications

  1. de Brouwer A, Yntema H, Kleefstra T, Lugtenberg D, Oudakker A, de Vries B, et al. Mutation frequencies of X-linked mental retardation genes in families from the EuroMRX consortium. Hum Mutat. 2007;28:207-8 pubmed
    ..Our results show that it is now possible to identify 42% of the genetic defects in non-syndromic and syndromic XLMR families with obligate female carriers...
  2. Ropers H, Hamel B. X-linked mental retardation. Nat Rev Genet. 2005;6:46-57 pubmed
    ..Here, we review the remarkable recent progress in this field, its promise for understanding neural function, learning and memory, and the implications of this research for health care...
  3. Gilfillan G, Selmer K, Roxrud I, Smith R, Kyllerman M, Eiklid K, et al. SLC9A6 mutations cause X-linked mental retardation, microcephaly, epilepsy, and ataxia, a phenotype mimicking Angelman syndrome. Am J Hum Genet. 2008;82:1003-10 pubmed publisher
    ..Therefore, mutations in SLC9A6 cause X-linked mental retardation. Additionally, males with findings suggestive of unexplained Angelman syndrome should be considered as potential candidates for SLC9A6 mutations...
  4. Abidi F, Miano M, Murray J, Schwartz C. A novel mutation in the PHF8 gene is associated with X-linked mental retardation with cleft lip/cleft palate. Clin Genet. 2007;72:19-22 pubmed
    ..Our finding further supports the hypothesis that the PHF8 protein may play an important role in cognitive function and midline formation...
  5. Mandel J, Chelly J. Monogenic X-linked mental retardation: is it as frequent as currently estimated? The paradox of the ARX (Aristaless X) mutations. Eur J Hum Genet. 2004;12:689-93 pubmed
    ..13%). We conclude that monogenic XLMR has much lower prevalence in male MR (< 10%) than the 23% that would be required to account for a 30% male excess of mental retardation...
  6. Wu Y, Arai A, Rumbaugh G, Srivastava A, Turner G, Hayashi T, et al. Mutations in ionotropic AMPA receptor 3 alter channel properties and are associated with moderate cognitive impairment in humans. Proc Natl Acad Sci U S A. 2007;104:18163-8 pubmed
    ..Our study provides the genetic and functional evidence that mutant iGluR3 with altered kinetic properties is associated with moderate cognitive impairment in humans...
  7. Tahiliani M, Mei P, Fang R, Leonor T, Rutenberg M, Shimizu F, et al. The histone H3K4 demethylase SMCX links REST target genes to X-linked mental retardation. Nature. 2007;447:601-5 pubmed
    ..We propose that loss of SMCX activity impairs REST-mediated neuronal gene regulation, thereby contributing to SMCX-associated X-linked mental retardation...
  8. Cilliers D, Parveen R, Clayton P, Cairns S, Clarke S, Shalet S, et al. A new X-linked mental retardation (XLMR) syndrome with late-onset primary testicular failure, short stature and microcephaly maps to Xq25-q26. Eur J Med Genet. 2007;50:216-23 pubmed
    ..However, the more severe mental retardation, muscle wasting and tremor described in this other family would suggest that our family is affected by a novel XLMR syndrome...
  9. Chiurazzi P, Tabolacci E, Neri G. X-linked mental retardation (XLMR): from clinical conditions to cloned genes. Crit Rev Clin Lab Sci. 2004;41:117-58 pubmed
    ..Eventually, DNA and protein microarray technologies will assist researchers and physicians in reaching a diagnosis even in small families or in individual patients with XLMR...

More Information

Publications66

  1. Castro N, dos Santos R, Nelson R, Beçak W, Hane B, Lindsey C, et al. Shashi XLMR syndrome: report of a second family. Am J Med Genet A. 2003;118A:49-51 pubmed
    ..2000: Am J Hum Genet 66:469-479]. Furthermore, haplotype analysis was consistent with localization of the Shashi XLMR syndrome in Xq26-q27. Thus, the family likely represents a second occurrence of the Shashi XLMR syndrome...
  2. Kleefstra T, Yntema H, Oudakker A, Banning M, Kalscheuer V, Chelly J, et al. Zinc finger 81 (ZNF81) mutations associated with X-linked mental retardation. J Med Genet. 2004;41:394-9 pubmed
  3. Tarpey P, Smith R, Pleasance E, Whibley A, Edkins S, Hardy C, et al. A systematic, large-scale resequencing screen of X-chromosome coding exons in mental retardation. Nat Genet. 2009;41:535-43 pubmed publisher
    ..The study has, however, also highlighted issues confronting whole-genome sequencing screens, including the observation that loss of function of 1% or more of X-chromosome genes is compatible with apparently normal existence. ..
  4. Field M, Tarpey P, Boyle J, Edkins S, Goodship J, Luo Y, et al. Mutations in the RSK2(RPS6KA3) gene cause Coffin-Lowry syndrome and nonsyndromic X-linked mental retardation. Clin Genet. 2006;70:509-15 pubmed
    ..These families show that strict reliance on classical clinical criteria for mutation testing may result in a missed diagnosis. A less targeted screening approach to mutation testing is advocated...
  5. Dibbens L, Tarpey P, Hynes K, Bayly M, Scheffer I, Smith R, et al. X-linked protocadherin 19 mutations cause female-limited epilepsy and cognitive impairment. Nat Genet. 2008;40:776-81 pubmed publisher
    ..PCDH19 is expressed in developing brains of human and mouse and is the first member of the cadherin superfamily to be directly implicated in epilepsy or mental retardation...
  6. Stevenson R, Schwartz C. Clinical and molecular contributions to the understanding of X-linked mental retardation. Cytogenet Genome Res. 2002;99:265-75 pubmed
    ..The genes involve signaling pathways, transcription factors, cytoskeletal organization, cell adhesion and migration, and maintenance of the cell membrane potential...
  7. Ropers H, Hoeltzenbein M, Kalscheuer V, Yntema H, Hamel B, Fryns J, et al. Nonsyndromic X-linked mental retardation: where are the missing mutations?. Trends Genet. 2003;19:316-20 pubmed
    ..In 83% of these families, underlying gene defects are not yet known. Our observations should speed up the search for mutations that are still missing and pave the way for the molecular diagnosis of this common disorder...
  8. Poirier K, Lacombe D, Gilbert Dussardier B, Raynaud M, Desportes V, de Brouwer A, et al. Screening of ARX in mental retardation families: Consequences for the strategy of molecular diagnosis. Neurogenetics. 2006;7:39-46 pubmed
    ..2%). This study confirms that the frequency of ARX mutations is high in XLMR, and the analysis of ARX in MRX should not be limited to duplication...
  9. Gecz J, Shoubridge C, Corbett M. The genetic landscape of intellectual disability arising from chromosome X. Trends Genet. 2009;25:308-16 pubmed publisher
    ..1% of the total landscape, which arguably remains only about half complete. There remain many hills to climb and valleys to cross before the ID landscape is fully triangulated...
  10. Tarpey P, Raymond F, O Meara S, Edkins S, Teague J, Butler A, et al. Mutations in CUL4B, which encodes a ubiquitin E3 ligase subunit, cause an X-linked mental retardation syndrome associated with aggressive outbursts, seizures, relative macrocephaly, central obesity, hypogonadism, pes cavus, and tremor. Am J Hum Genet. 2007;80:345-52 pubmed
    ..The relatively high frequency of CUL4B mutations in this series indicates that it is one of the most commonly mutated genes underlying XLMR and suggests that its introduction into clinical diagnostics should be a high priority...
  11. Gestinari Duarte R, Santos Rebouças C, Boy R, Pimentel M. ARX mutation c.428-451dup (24bp) in a Brazilian family with X-linked mental retardation. Eur J Med Genet. 2006;49:269-75 pubmed
    ..This duplication leads to an expansion of the second polyalanine tract of ARX protein. We have reported the identification of a Brazilian family segregating the c.428-451 dup (24 bp) in ARX gene...
  12. Tarpey P, Raymond F, Nguyen L, Rodriguez J, Hackett A, Vandeleur L, et al. Mutations in UPF3B, a member of the nonsense-mediated mRNA decay complex, cause syndromic and nonsyndromic mental retardation. Nat Genet. 2007;39:1127-33 pubmed
    ..The UPF3B protein is an important component of the NMD surveillance machinery. Our results directly implicate abnormalities of NMD in human disease and suggest at least partial redundancy of NMD pathways. ..
  13. Marco E, Abidi F, Bristow J, Dean W, Cotter P, Jeremy R, et al. ARHGEF9 disruption in a female patient is associated with X linked mental retardation and sensory hyperarousal. J Med Genet. 2008;45:100-5 pubmed
    ..We identified a female patient with mental retardation and sensory hyperarousal. She has a de novo paracentric inversion of one X chromosome with completely skewed inactivation of the normal X chromosome...
  14. Molinari F, Foulquier F, Tarpey P, Morelle W, Boissel S, Teague J, et al. Oligosaccharyltransferase-subunit mutations in nonsyndromic mental retardation. Am J Hum Genet. 2008;82:1150-7 pubmed publisher
    ..Together, our results demonstrate that fine regulation of OTase activity is essential for normal cognitive-function development, providing therefore further insights to understand the pathophysiological bases of MR...
  15. Field M, Tarpey P, Smith R, Edkins S, O Meara S, Stevens C, et al. Mutations in the BRWD3 gene cause X-linked mental retardation associated with macrocephaly. Am J Hum Genet. 2007;81:367-74 pubmed
    ..BRWD3 is therefore a new gene implicated in the etiology of XLMR associated with macrocephaly and may cause disease by altering intracellular signaling pathways affecting cellular proliferation...
  16. Medina C, Mazerolle C, Wang Y, Berube N, Coupland S, Gibbons R, et al. Altered visual function and interneuron survival in Atrx knockout mice: inference for the human syndrome. Hum Mol Genet. 2009;18:966-77 pubmed publisher
    ..These results implicate a role for Atrx in interneuron survival and differentiation...
  17. Annunziata I, Lanzara C, Conte I, Zullo A, Ventruto V, Rinaldi M, et al. Mapping of MRX81 in Xp11.2-Xq12 suggests the presence of a new gene involved in nonspecific X-linked mental retardation. Am J Med Genet A. 2003;118A:217-22 pubmed
    ..So far, automated sequencing of two candidates in the region, the MRX gene oligophrenin (OPHN1) and the brain-specific ephrinB1 (EFNB1) gene, in DNA from affected males excluded their candidacy for MRX81, suggesting a novel disease gene...
  18. Shoichet S, Hoffmann K, Menzel C, Trautmann U, Moser B, Hoeltzenbein M, et al. Mutations in the ZNF41 gene are associated with cognitive deficits: identification of a new candidate for X-linked mental retardation. Am J Hum Genet. 2003;73:1341-54 pubmed
    ..Our results suggest that ZNF41 is critical for cognitive development; further studies aim to elucidate the specific mechanisms by which ZNF41 alterations lead to MR...
  19. Partington M, Turner G, Boyle J, Gecz J. Three new families with X-linked mental retardation caused by the 428-451dup(24bp) mutation in ARX. Clin Genet. 2004;66:39-45 pubmed
    ..5%. Characteristic dystonic movements of the hands were seen in 63% and dysarthria in 54%. The focal dystonia, in association with mental retardation, may prove to be diagnostic of this mutation...
  20. Colombo E, Galli R, Cossu G, Gecz J, Broccoli V. Mouse orthologue of ARX, a gene mutated in several X-linked forms of mental retardation and epilepsy, is a marker of adult neural stem cells and forebrain GABAergic neurons. Dev Dyn. 2004;231:631-9 pubmed
    ..In conclusion, our mouse Arx expression data provide important further insights into the puzzling complexity of the human ARX mutation pleiotropy...
  21. Lugtenberg D, Yntema H, Banning M, Oudakker A, Firth H, Willatt L, et al. ZNF674: a new kruppel-associated box-containing zinc-finger gene involved in nonsyndromic X-linked mental retardation. Am J Hum Genet. 2006;78:265-78 pubmed
    ..Identification of ZNF674 as the third XLMR gene in this cluster may indicate a common role for these zinc-finger genes that is crucial to human cognitive functioning...
  22. Najm J, Horn D, Wimplinger I, Golden J, Chizhikov V, Sudi J, et al. Mutations of CASK cause an X-linked brain malformation phenotype with microcephaly and hypoplasia of the brainstem and cerebellum. Nat Genet. 2008;40:1065-7 pubmed publisher
    ..All five affected individuals with CASK mutations had congenital or postnatal microcephaly, disproportionate brainstem and cerebellar hypoplasia, and severe mental retardation...
  23. Schwartz C, Tarpey P, Lubs H, Verloes A, May M, Risheg H, et al. The original Lujan syndrome family has a novel missense mutation (p.N1007S) in the MED12 gene. J Med Genet. 2007;44:472-7 pubmed
    ..Thus, it seems that these two X-linked mental retardation syndromes are allelic, with mutations in the MED12 gene...
  24. Kohn M, Kehrer Sawatzki H, Steinbach P, Marshall Graves J, Hameister H. Recruitment of old genes to new functions: evidences obtained by comparing the orthologues of human XLMR genes in mouse and chicken. Cytogenet Genome Res. 2007;116:173-80 pubmed
    ..Also in the testes, specific expression was only found in mouse, not in chicken. These data are interpreted such that certain genes on the X chromosome gained novel functions during evolution...
  25. Tarpey P, Stevens C, Teague J, Edkins S, O Meara S, Avis T, et al. Mutations in the gene encoding the Sigma 2 subunit of the adaptor protein 1 complex, AP1S2, cause X-linked mental retardation. Am J Hum Genet. 2006;79:1119-24 pubmed
    ..AP1S2 is the first reported XLMR gene that encodes a protein directly involved in the assembly of endocytic vesicles...
  26. Madrigal I, Rodriguez Revenga L, Badenas C, Sanchez A, Martinez F, Fernandez I, et al. MLPA as first screening method for the detection of microduplications and microdeletions in patients with X-linked mental retardation. Genet Med. 2007;9:117-22 pubmed
    ..Multiplex ligation probe amplification is a recently developed technique based on the amplification of specific probes that allows relative quantification of 40 to 46 different target DNA sequences in a single reaction...
  27. Chiurazzi P, Schwartz C, Gecz J, Neri G. XLMR genes: update 2007. Eur J Hum Genet. 2008;16:422-34 pubmed publisher
    ..We briefly consider the molecular function of known XLMR proteins and discuss the possible strategies to identify the remaining XLMR genes. Final remarks are made on the natural history of XLMR conditions and on diagnostic issues...
  28. Kleefstra T, Franken C, Arens Y, Ramakers G, Yntema H, Sistermans E, et al. Genotype-phenotype studies in three families with mutations in the polyglutamine-binding protein 1 gene (PQBP1). Clin Genet. 2004;66:318-26 pubmed
    ..These observations contribute to the phenotypic knowledge of patients with PQBP1 mutations and make this XLMR syndrome well recognizable to clinicians...
  29. Lugtenberg D, de Brouwer A, Kleefstra T, Oudakker A, Frints S, Schrander Stumpel C, et al. Chromosomal copy number changes in patients with non-syndromic X linked mental retardation detected by array CGH. J Med Genet. 2006;43:362-70 pubmed
    ..In this study, 40 patients with non-specific X linked mental retardation were analysed with full coverage, X chromosomal, bacterial artificial chromosome arrays...
  30. Raymond F, Tarpey P, Edkins S, Tofts C, O Meara S, Teague J, et al. Mutations in ZDHHC9, which encodes a palmitoyltransferase of NRAS and HRAS, cause X-linked mental retardation associated with a Marfanoid habitus. Am J Hum Genet. 2007;80:982-7 pubmed
    ..Furthermore, now that the first palmitoyltransferase that causes mental retardation has been identified, defects in other palmitoylation transferases become good candidates for causing other mental retardation syndromes...
  31. Wada T, Sugie H, Fukushima Y, Saitoh S. Non-skewed X-inactivation may cause mental retardation in a female carrier of X-linked alpha-thalassemia/mental retardation syndrome (ATR-X): X-inactivation study of nine female carriers of ATR-X. Am J Med Genet A. 2005;138:18-20 pubmed
    ..These findings suggest that mutations in ATRX may cause mental retardation in females, if the X chromosome carrying mutated ATRX is not properly inactivated...
  32. Koolen D, Pfundt R, de Leeuw N, Hehir Kwa J, Nillesen W, Neefs I, et al. Genomic microarrays in mental retardation: a practical workflow for diagnostic applications. Hum Mutat. 2009;30:283-92 pubmed publisher
    ..2% (71.9% losses, 19.6% gains, 8.5% complex) could be identified, reflecting the overall diagnostic yield of clinically significant CNVs in individuals with unexplained mental retardation...
  33. Ropers H. Genetics of intellectual disability. Curr Opin Genet Dev. 2008;18:241-50 pubmed publisher
    ..Ongoing studies into the function of ID genes are shedding more light on the pathogenesis of this disorder, and there is reason to believe that at least some genetic forms of ID may be amenable to drug treatment...
  34. Froyen G, Corbett M, Vandewalle J, Jarvela I, Lawrence O, Meldrum C, et al. Submicroscopic duplications of the hydroxysteroid dehydrogenase HSD17B10 and the E3 ubiquitin ligase HUWE1 are associated with mental retardation. Am J Hum Genet. 2008;82:432-43 pubmed publisher
    ..Our findings demonstrate that an increased gene dosage of HSD17B10, HUWE1, or both contribute to the etiology of XLMR and suggest that point mutations in HUWE1 are associated with this disease too...
  35. Bauters M, Van Esch H, Marynen P, Froyen G. X chromosome array-CGH for the identification of novel X-linked mental retardation genes. Eur J Med Genet. 2005;48:263-75 pubmed
  36. Abidi F, Cardoso C, Lossi A, Lowry R, Depetris D, Mattei M, et al. Mutation in the 5' alternatively spliced region of the XNP/ATR-X gene causes Chudley-Lowry syndrome. Eur J Hum Genet. 2005;13:176-83 pubmed
    ..Our data suggest that ChLS is allelic to the ATR-X syndrome with its less severe phenotype being due to the presence of some XNP/ATR-X protein...
  37. Berube N, Mangelsdorf M, Jagla M, Vanderluit J, Garrick D, Gibbons R, et al. The chromatin-remodeling protein ATRX is critical for neuronal survival during corticogenesis. J Clin Invest. 2005;115:258-67 pubmed
    ..Taken together, our results indicate that ATRX is a critical mediator of cell survival during early neuronal differentiation. Thus, increased neuronal loss may contribute to the severe mental retardation observed in human patients...
  38. Kleine Kohlbrecher D, Christensen J, Vandamme J, Abarrategui I, Bak M, Tommerup N, et al. A functional link between the histone demethylase PHF8 and the transcription factor ZNF711 in X-linked mental retardation. Mol Cell. 2010;38:165-78 pubmed publisher
  39. Koivisto A, Ala Mello S, Lemmelä S, Komu H, Rautio J, Jarvela I. Screening of mutations in the PHF8 gene and identification of a novel mutation in a Finnish family with XLMR and cleft lip/cleft palate. Clin Genet. 2007;72:145-9 pubmed
    ..The mutation was not present in 200 anonymous blood donors (approximately 300 X-chromosomes). To our knowledge, F279S is the third mutation of the PHF8 gene identified so far...
  40. Iwase S, Lan F, Bayliss P, de la Torre Ubieta L, Huarte M, Qi H, et al. The X-linked mental retardation gene SMCX/JARID1C defines a family of histone H3 lysine 4 demethylases. Cell. 2007;128:1077-88 pubmed
    ..Our findings thus identify a family of H3K4me3 demethylases and uncover a critical link between histone modifications and XLMR...
  41. Kalscheuer V, Freude K, Musante L, Jensen L, Yntema H, Gecz J, et al. Mutations in the polyglutamine binding protein 1 gene cause X-linked mental retardation. Nat Genet. 2003;35:313-5 pubmed
    ..PQBP1 has previously been implicated in the pathogenesis of polyglutamine expansion diseases. Our findings link this gene to XLMR and shed more light on the pathogenesis of this common disorder...
  42. Nawara M, Szczaluba K, Poirier K, Chrzanowska K, Pilch J, Bal J, et al. The ARX mutations: a frequent cause of X-linked mental retardation. Am J Med Genet A. 2006;140:727-32 pubmed
    ..These data, together with those reported in the literature, imply that screening for c.428-451 dup (24 bp) mutation should be recommended in all patients with suspected XLMR...
  43. Poirier K, Abriol J, Souville I, Laroche Raynaud C, Beldjord C, Gilbert B, et al. Maternal mosaicism for mutations in the ARX gene in a family with X linked mental retardation. Hum Genet. 2005;118:45-8 pubmed
    ..We thus show that the mother displays somatic mosaicism for the duplication thereby highlighting the need to reconsider the molecular screening in sporadic cases of MR...
  44. Laumonnier F, Holbert S, Ronce N, Faravelli F, Lenzner S, Schwartz C, et al. Mutations in PHF8 are associated with X linked mental retardation and cleft lip/cleft palate. J Med Genet. 2005;42:780-6 pubmed
    ..were found in the PHF8 gene (encoding the PHD finger protein 8) in two unrelated families with X linked mental retardation (XLMR) associated with cleft lip/palate (MIM 300263)...
  45. Ropers H. X-linked mental retardation: many genes for a complex disorder. Curr Opin Genet Dev. 2006;16:260-9 pubmed
    ..Eventually, even therapy of XLMR might become possible, as suggested by the unexpected plasticity of the neuronal wiring in the brain, and the recent successful drug treatment of a fly model for fragile X syndrome...
  46. Govek E, Newey S, Akerman C, Cross J, Van der Veken L, Van Aelst L. The X-linked mental retardation protein oligophrenin-1 is required for dendritic spine morphogenesis. Nat Neurosci. 2004;7:364-72 pubmed
    ..We further demonstrate an interaction between oligophrenin-1 and the postsynaptic adaptor protein Homer. Our findings provide the first insight into how mutations in a Rho-linked MRX gene may compromise neuronal function...
  47. Inlow J, Restifo L. Molecular and comparative genetics of mental retardation. Genetics. 2004;166:835-81 pubmed
    ..We selected 42 Drosophila orthologs as most likely to reveal molecular and cellular mechanisms of nervous system development or plasticity relevant to MR...
  48. Jensen L, Lenzner S, Moser B, Freude K, Tzschach A, Wei C, et al. X-linked mental retardation: a comprehensive molecular screen of 47 candidate genes from a 7.4 Mb interval in Xp11. Eur J Hum Genet. 2007;15:68-75 pubmed
    ..We show that many of the studied genes are unlikely to play a major role in MRX. This information will help to avoid duplication of efforts in the ongoing endeavor to unravel the molecular causes of MRX...
  49. Stepp M, Cason A, Finnis M, Mangelsdorf M, Holinski Feder E, Macgregor D, et al. XLMR in MRX families 29, 32, 33 and 38 results from the dup24 mutation in the ARX (Aristaless related homeobox) gene. BMC Med Genet. 2005;6:16 pubmed
    ..The most frequent mutation in this gene is a 24 bp duplication in exon 2. Based on this fact, a panel of XLMR families linked to Xp22 was tested for this particular ARX mutation...
  50. Qi H, Sarkissian M, Hu G, Wang Z, Bhattacharjee A, Gordon D, et al. Histone H4K20/H3K9 demethylase PHF8 regulates zebrafish brain and craniofacial development. Nature. 2010;466:503-7 pubmed publisher
    ..Our findings indicate that an imbalance of histone methylation dynamics has a critical role in XLMR. ..
  51. Froyen G, Bauters M, Voet T, Marynen P. X-linked mental retardation and epigenetics. J Cell Mol Med. 2006;10:808-25 pubmed
    ..It is therefore tempting to speculate that the cognitive deficit in a significant percentage of patients with unexplained mental retardation results from epigenetic modifications. ..
  52. Madrigal I, Rodriguez Revenga L, Armengol L, Gonzalez E, Rodriguez B, Badenas C, et al. X-chromosome tiling path array detection of copy number variants in patients with chromosome X-linked mental retardation. BMC Genomics. 2007;8:443 pubmed
    ..20%). This tiling path array of the human X chromosome has proven successful for the detection and characterization of known rearrangements and novel CNVs in XLMR patients. ..
  53. Rio M, Malan V, Boissel S, Toutain A, Royer G, Gobin S, et al. Familial interstitial Xq27.3q28 duplication encompassing the FMR1 gene but not the MECP2 gene causes a new syndromic mental retardation condition. Eur J Hum Genet. 2010;18:285-90 pubmed publisher
    ..This family broadens the phenotypic spectrum of FMR1 anomalies in an unexpected manner, and we suggest that this condition may represent the fragile X syndrome "contre-type". ..
  54. Christodoulou J, Weaving L. MECP2 and beyond: phenotype-genotype correlations in Rett syndrome. J Child Neurol. 2003;18:669-74 pubmed
  55. Rauch A, Hoyer J, Guth S, Zweier C, Kraus C, Becker C, et al. Diagnostic yield of various genetic approaches in patients with unexplained developmental delay or mental retardation. Am J Med Genet A. 2006;140:2063-74 pubmed
    ..If molecular karyotyping is not available, subtelomeric screening should be performed...
  56. Mancini G, Catsman Berrevoets C, de Coo I, Aarsen F, Kamphoven J, Huijmans J, et al. Two novel mutations in SLC6A8 cause creatine transporter defect and distinctive X-linked mental retardation in two unrelated Dutch families. Am J Med Genet A. 2005;132A:288-95 pubmed
  57. Braun D, Wirth E, Schweizer U. Thyroid hormone transporters in the brain. Rev Neurosci. 2010;21:173-86 pubmed
    ..Hence, the many roles played by thyroid hormones in the development, function, and regeneration of the nervous system are dependent on the spatiotemporal expression of several transmembrane transport proteins...