title: Finding new etiologies of mental retardation and hypotonia: X marks the spot.
abstract: Mental retardation (MR) and hypotonia occur together frequently and have a heterogeneous etiology. Molecular and clinical studies have led to the recent discovery of genes on the X chromosome that may be associated with syndromal forms of X-linked MR (XLMR). These disorders manifest additional neurological and somatic features that are helpful in establishing a specific diagnosis and etiology. This article provides an overview of MR and its association with hypotonia, with a review of five 'new' XLMR-hypotonia syndromes.
authors.affiliation: Greenwood Genetic Center, Greenwood, SC, USA. crogers@ggc.org
authors.forename: R Curtis
authors.initials: RC
authors.lastname: Rogers
authors.forename: Roger E
authors.initials: RE
authors.lastname: Stevenson
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Simensen
authors.forename: Kenton R
authors.initials: KR
authors.lastname: Holden
authors.forename: Charles E
authors.initials: CE
authors.lastname: Schwartz
mesh_terms: D002648:Child; D041321:Chromosomes, Human, X; D006801:Humans; D026901:Membrane Transport Proteins / Q000172:deficiency; D038901:X-Linked Intellectual Disability / Q000235:genetics*; D051783:Methyl-CpG-Binding Protein 2 / Q000235:genetics; D027501:Monocarboxylic Acid Transporters / Q000235:genetics; D009123:Muscle Hypotonia / Q000235:genetics*; D009128:Muscle Spasticity / Q000235:genetics; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics; D050480:Plasma Membrane Neurotransmitter Transport Proteins / Q000235:genetics; D025064:Sex Chromosome Disorders / Q000175:diagnosis* / Q000235:genetics; D013097:Spermine Synthase / Q000172:deficiency; D027981:Symporters; D017085:alpha-Thalassemia / Q000175:diagnosis
chemical_list: C497392:MECP2 protein, human; D026901:Membrane Transport Proteins; D051783:Methyl-CpG-Binding Protein 2; D027501:Monocarboxylic Acid Transporters; D009419:Nerve Tissue Proteins; D050480:Plasma Membrane Neurotransmitter Transport Proteins; C090735:SLC16A2 protein, human; C094770:SLC6A8 protein, human; D027981:Symporters; C080679:creatine transporter; D013097:Spermine Synthase