Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Opitz-Kaveggia syndrome (also known as FG syndrome) is an X-linked disorder characterized by mental retardation, relative macrocephaly, hypotonia and constipation. We report here that the original family for whom the condition is named and five other families have a recurrent mutation (2881C>T, leading to R961W) in MED12 (also called TRAP230 or HOPA), a gene located at Xq13 that functions as a thyroid receptor-associated protein in the Mediator complex.
 ...
PMID:A recurrent mutation in MED12 leading to R961W causes Opitz-Kaveggia syndrome. 1733 63

The Mediator complex is a fluid assemblage of approximately 25 proteins that is essential for eukaryotic transcriptional regulation. Mediator of RNA polymerase II transcription (MED)12 (HOPA) is a 25-kb Xq13 member of the Mediator complex that plays a key role in the complex and directly moderates receptor tyrosine kinase, nuclear receptor and Wnt pathway signaling. Sequence variation in two MED12 protein domains has been linked to neuropsychiatric illness. First, variants in the Leu-Ser domain have been linked to Opitz-Kaveggia and Lujan syndromes, which are forms of X-linked mental retardation. Second, a balanced polymorphism in the C terminus opposite-paired domain, a key motif in the MED12-mediated transcriptional repression of Wnt signaling, has been associated with increased risk for psychosis. We conclude that variation of MED12 is associated with a wide variety of clinical presentations whose severity is dependent on the location and nature of the variation, and that a thorough understanding of MED12's role in transcriptional regulation could have significant benefits for human healthcare.
 ...
PMID:Role of MED12 in transcription and human behavior. 1771 26

Mediator occupies a central role in RNA polymerase II transcription as a sensor, integrator, and processor of regulatory signals that converge on protein-coding gene promoters. Compared to its role in gene activation, little is known regarding the molecular mechanisms and biological implications of Mediator as a transducer of repressive signals. Here we describe a protein interaction network required for extraneuronal gene silencing comprising Mediator, G9a histone methyltransferase, and the RE1 silencing transcription factor (REST; also known as neuron restrictive silencer factor, NRSF). We show that the MED12 interface in Mediator links REST with G9a-dependent histone H3K9 dimethylation to suppress neuronal genes in nonneuronal cells. Notably, missense mutations in MED12 causing the X-linked mental retardation (XLMR) disorders FG syndrome and Lujan syndrome disrupt its REST corepressor function. These findings implicate Mediator in epigenetic restriction of neuronal gene expression to the nervous system and suggest a pathologic basis for MED12-associated XLMR involving impaired REST-dependent neuronal gene regulation.
 ...
PMID:Mediator links epigenetic silencing of neuronal gene expression with x-linked mental retardation. 1869 61

Opitz and Kaveggia [Opitz and Kaveggia (1974); Z Kinderheilk 117:1-18] reported on a family of five affected males with distinctive facial appearance, mental retardation, macrocephaly, imperforate anus and hypotonia. Risheg et al. [Risheg et al. (2007); Nat Genet 39:451-453] identified an identical mutation (p.R961W) in MED12 in six families with Opitz-Kaveggia syndrome, including a surviving affected man from the family reported in 1974. The previously defined behavior phenotype of hyperactivity, affability, and excessive talkativeness is very frequent in young boys with this mutation, along with socially oriented, attention-seeking behaviors. We present case studies of two older males with FG syndrome and the p.R961W mutation to illustrate how their behavior changes with age. We also characterize the behavior of eight additional individuals with FG syndrome and this recurrent mutation in MED12 using the Vineland Adaptive Behavior Scales 2nd edition, the Reiss Profile of Fundamental Goals and Motivation Sensitivities, and the Achenbach Child Behavior Checklist. Males with this MED12 mutation had deficits in communication skills compared to their socialization and daily living skills. In addition, they were at increased risk for maladaptive behavior, with a propensity towards aggression, anxiety, and inattention. Based on the behavior phenotype in 10 males with this recurrent MED12 mutation, we offer specific recommendations and interventional strategies. Our findings reinforce the importance of testing for the p.R961W MED12 mutation in males who are suspected of having developmental and behavioral problems with a clinical phenotype that is consistent with FG syndrome.
 ...
PMID:Behavior of 10 patients with FG syndrome (Opitz-Kaveggia syndrome) and the p.R961W mutation in the MED12 gene. 1897 76

First described in 1974, FG syndrome (FGS) is an X-linked multiple congenital anomaly/mental retardation (MCA/MR) disorder, characterized by high clinical variability and genetic heterogeneity. Five loci (FGS1-5) have so far been linked to this phenotype on the X chromosome, but only one gene, MED12, has been identified to date. Mutations in this gene account for a restricted number of FGS patients with a more distinctive phenotype, referred to as the Opitz-Kaveggia phenotype. We report here that a p.R28L (c.83G-->T) missense mutation in CASK causes FGS phenotype in an Italian family previously mapped to Xp11.4-p11.3 (FGS4). The identified missense mutation cosegregates with the phenotype in this family and is absent in 1000 control X chromosomes of the same ethnic origin. An extensive analysis of CASK protein functions as well as structural and dynamic studies performed by molecular dynamics (MD) simulation did not reveal significant alterations induced by the p.R28L substitution. However, we observed a partial skipping of the exon 2 of CASK, presumably a consequence of improper recognition of exonic splicing enhancers (ESEs) induced by the c.83G-->T transversion. CASK is a multidomain scaffold protein highly expressed in the central nervous system (CNS) with specific localization to the synapses, where it forms large signaling complexes regulating neurotransmission. We suggest that the observed phenotype is most likely a consequence of an altered CASK expression profile during embryogenesis, brain development, and differentiation.
 ...
PMID:A missense mutation in CASK causes FG syndrome in an Italian family. 1920 May 22

FG syndrome is a rare X-linked multiple congenital anomaly-cognitive impairment disorder caused by the p.R961W mutation in the MED12 gene. We identified all known patients with this mutation to delineate their clinical phenotype and devise a clinical algorithm to facilitate molecular diagnosis. We ascertained 23 males with the p.R961W mutation in MED12 from 9 previously reported FG syndrome families and 1 new family. Six patients are reviewed in detail. These 23 patients were compared with 48 MED12 mutation-negative patients, who had the clinical diagnosis of FG syndrome. Traits that best discriminated between these two groups were chosen to develop an algorithm with high sensitivity and specificity for the p.R961W MED12 mutation. FG syndrome has a recognizable dysmorphic phenotype with a high incidence of congenital anomalies. A family history of X-linked mental retardation, deceased male infants, and/or multiple fetal losses was documented in all families. The algorithm identifies the p.R961W MED12 mutation-positive group with 100% sensitivity and 90% specificity. The clinical phenotype of FG syndrome defines a recognizable pattern of X-linked multiple congenital anomalies and cognitive impairment. This algorithm can assist the clinician in selecting the patients for testing who are most likely to have the recurrent p.R961W MED12 mutation.
 ...
PMID:FG syndrome, an X-linked multiple congenital anomaly syndrome: the clinical phenotype and an algorithm for diagnostic testing. 1993 45

Opitz and Kaveggia [Opitz and Kaveggia (1974); Z Kinderheilkd 117:1-18] reported on a family of five affected males with distinctive facial appearance, mental retardation, macrocephaly, imperforate anus, and hypotonia. Risheg et al. [Risheg et al. (2007); Nature Genetics 39:451-453] identified an identical mutation (p.R961W) in MED12 in six families with Opitz-Kaveggia syndrome, including a surviving affected man from the original family reported in 1974. The previously described behavior phenotype of hyperactivity, affability, and excessive talkativeness is very frequent in young boys with FG syndrome, along with socially oriented, attention-seeking behaviors. We present case studies of five adult males who were previously published with the clinical diagnosis of FG syndrome and then subsequently proven by Risheg et al. [Risheg et al. (2007); Nature Genetics 39:451-453] to have the recurrent p.R961W mutation. These individuals had episodic and longstanding behavior patterns, sometimes aggressive or self-abusing, that occurred more frequently in puberty and early adulthood. We try to describe the triggers for these behaviors, indicate how these behaviors change with advancing age, and suggest specific recommendations and interventional strategies based on the clinical histories of affected adolescent males with FG syndrome [Graham et al., 2008; Clark et al., 2009]. Young men who exhibit these behaviors may benefit from a careful examination to detect medical problems, use of mood stabilizers if needed, and/or behavioral intervention. The transition to a community living situation can be challenging without careful planning and timely behavioral intervention. They remain impulsive and can have aggressive outbursts when making the transition to adult life, but these challenges can be managed, as demonstrated by these clinical histories.
 ...
PMID:Behavioral features in young adults with FG syndrome (Opitz-Kaveggia syndrome). 2098 78

Lujan-Fryns Syndrome (LFS) is defined as a set of symptoms including mild-moderate mental retardation, marfanoid appearance, hypotonia at birth, hypernasal speech, characteristic craniofacial appearance and normal testis size. The frequency of the syndrome is not known thus the information obtained is solely based on case reports. Hereby, we present a patient with LFS diagnosis. The 29-year old male patient had mental retardation, aggression, and persecutory delusions, characteristic craniofacial and marfanoid features. During his speech pronominal reversal was observed ('the hurt him, he is so upset' when talking abour himself). After examination and genetic analysis, fragile X, Klinefelter, Marfan and Down syndromes and homocystinuria were eliminated as causes of mental retardation. A preliminary diagnoses of LFS done. No mutation was detected in exon 22 of the MED12 gene; but. Whole Exome Sequencing (WES) is ongoing. The patient was started on risperidone (4 mg/day) for psychotic symptoms and carbamazepine (200 mg/day) for impulse control and as an antiepileptic. After a follow up of 8 months, impulse control, psychotic symptoms and aggression improved significantly. Since the specific gene mutation of LFS was not determined in our case, we solely had to depend on clinical evaluation and genetic analysis. Although it is not easy to fully define or classify these syndromes, we believe every reported case will be a step in overcoming these difficulties.
 ...
PMID:Lujan-Fryns Syndrome Phenotype with Autism-Like Behavior and Atypical Psychotic Symptoms: Case Report. 3297 58