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Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We investigated the relationship between macroscopic entropy and microscopic complexity of the dynamics of body rocking and sitting still across adults with stereotyped movement disorder and mental retardation (profound and severe) against controls matched for age, height, and weight. This analysis was performed through the examination of center of pressure (COP) motion on the mediolateral (side-to-side) and anteroposterior (fore-aft) dimensions and the entropy of the relative phase between the two dimensions of motion. Intentional body rocking and stereotypical body rocking possessed similar slopes for their respective frequency spectra, but differences were revealed during maintenance of sitting postures. The dynamics of sitting in the control group produced lower spectral slopes and higher complexity (approximate entropy). In the controls, the higher complexity found on each dimension of motion was related to a weaker coupling between dimensions. Information entropy of the relative phase between the two dimensions of COP motion and irregularity (complexity) of their respective motions fitted a power-law function, revealing a relationship between macroscopic entropy and microscopic complexity across both groups and behaviors. This power-law relation affords the postulation that the organization of movement and posture dynamics occurs as a fractal process.
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PMID:Power-law scaling for macroscopic entropy and microscopic complexity: evidence from human movement and posture. 1659 66

The relation between the movement dynamic properties of sitting still and of seated body-rocking in adults with stereotyped movement disorder and mental retardation and a contrast group of typically developing age-matched adults was examined. Continuous measurement of sequential displacements in center-of-pressure was made using a force platform while subjects were engaged in seated body-rocking and quiet sitting. Properties of movement were compared across conditions (rocking, sitting) and groups (stereotyped movement disorder, contrast). The contrast group had the same modal frequency for both movement properties. The intrinsic dynamics of the stereotyped movement disorder group were similar to those of the contrast group for body-rocking but very different for quiet sitting. Findings support the suggestion that body-rocking in stereotyped movement disorder originates partly as an adaptation to an inability to control posture in a seated position.
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PMID:Dynamical origins of stereotypy: relation of postural movements during sitting to stereotyped movements during body-rocking. 1718 92

Maple syrup urine disease is a disorder of branched-chain keto acid metabolism. Three children were diagnosed with the intermediate form of maple syrup urine disease during routine evaluation of mental retardation. Clinical features were characterized by mental retardation, seizures, autistic features, and movement disorder in the form of dystonia. High-performance liquid chromatography of the urine and serum revealed elevated levels of branched-chain amino acids, suggesting a diagnosis of maple syrup urine disease. Magnetic resonance imaging showed diffuse hyperintense signals in the white matter along with involvement of the thalami and globus pallidus. Magnetic resonance imaging in the intermediate form showed myelination in the posterior limb of the internal capsule, in contrast to the classic form of the disease. Knowledge about the neuroimaging findings of this rare disease will help to narrow down the differential diagnosis when evaluating children with unexplained mental retardation and seizures.
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PMID:Intermediate maple syrup urine disease: neuroimaging observations in 3 patients from South India. 1771 90

Woodhouse Sakati syndrome is a rare autosomal recessive neuroendocrine disorder characterized by the combination of alopecia, hypogonadism, diabetes mellitus, mental retardation, sensory neural deafness and extrapyramidal features. Movement disorders mainly consist of dystonia and chorea of the limbs with onset in adolescence. Facial muscles are usually spared, but dysarthria is common. Pyramidal features and peripheral abnormalities are inconsistent features. Most of the reported families are from the Middle Eastern countries although rarely Caucasian cases have been described. Here we present clinical details of two affected siblings from a new Middle East family and draw attention of movement disorder specialists to this entity. We summarize findings from pervious cases with particular focus on neurological and movement disorder features.
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PMID:Dystonia in the Woodhouse Sakati syndrome: A new family and literature review. 1817 54

Movement disorders other than late onset tremor-ataxia in association with fragile X syndrome, the most common identifiable cause of inherited mental retardation, seem to be rare. Here we describe five male patients from three unrelated families with fragile X syndrome that presented with motor and phonic tics. Clinically, 4 patients fulfilled diagnostic criteria for Gilles de la Tourette syndrome (GTS) while 1 patient would have been diagnosed with an adult onset tic disorder. However, in all patients onset of tics was considerably later than in typical GTS. Three patients had atypical tics and two patients reported waxing and waning of tic intensity over time. Four of the 5 patients showed clinical signs typical of fragile X syndrome, in particular dysmorphic features, learning difficulties and speech and language problems that required special treatment. All patients had co-morbidities common to both GTS and fragile X syndrome. We suggest considering fragile X syndrome in GTS complicated by co-morbidity with late onset of atypical tics, in particular when learning disability and dysmorphic features are present.
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PMID:Fragile X syndrome associated with tic disorders. 1838 11

Mutations in the ARX gene are responsible for a wide variety of mental retardation conditions including X-linked infantile spasms (ISSX) and generalized dystonia. However, electroclinical descriptions in patients with ISSX carrying ARX mutations are scarce. Here, we report on the electroclinical features of a 4-year-old boy with an expansion of the trinucleotide repeat in the ARX gene. Epilepsy started at 2 months of age with subclinical spasms that consisted of episodes of eye rolling combined with atypical hypsarrhythmia. Later, the condition evolved into severe mental retardation with polymorphic ictal episodes that consisted of nocturnal brief axial contractions followed by dyskinetic movement of all four limbs and diurnal clusters of chaotic movements combined with myoclonic jerks. EEG recording of these episodes lead to the diagnosis of non-ictal dyskinetic movements. This combination of early infantile spasms followed by a complex movement disorder contributes further to extent the pleiotropy of the ARX-linked "interneuronopathy" and should lead the clinician to ARX mutation screening.
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PMID:Combination of infantile spasms, non-epileptic seizures and complex movement disorder: a new case of ARX-related epilepsy. 1846 66

While the function of dystrophin in muscle disease has been thoroughly investigated, dystrophin and associated proteins also have important roles in the central nervous system. Many patients with Duchenne and Becker muscular dystrophies (D/BMD) have cognitive impairment, learning disability, and an increased incidence of some neuropsychiatric disorders. Accordingly, dystrophin and members of the dystrophin-associated glycoprotein complex (DGC) are found in the brain where they participate in macromolecular assemblies that anchor receptors to specialized sites within the membrane. In neurons, dystrophin and the DGC participate in the postsynaptic clustering and stabilization of some inhibitory GABAergic synapses. During development, alpha-dystroglycan functions as an extracellular matrix receptor controlling, amongst other things, neuronal migration in the developing cortex and cerebellum. Several types of congenital muscular dystrophy caused by impaired alpha-dystroglycan glycosylation cause neuronal migration abnormalities and mental retardation. In glial cells, the DGC is involved in the organization of protein complexes that target water-channels to the plasma membrane. Finally, mutations in the gene encoding epsilon-sarcoglycan cause the neurogenic movement disorder, myoclonus-dystonia syndrome implicating epsilon-sarcoglycan in dopaminergic neurotransmission. In this review we describe the recent progress in defining the role of the DGC and associated proteins in the brain.
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PMID:The neurobiology of the dystrophin-associated glycoprotein complex. 1917 27

Glucose transporter-1 deficiency syndrome is caused by mutations in the SLC2A1 gene in the majority of patients and results in impaired glucose transport into the brain. From 2004-2008, 132 requests for mutational analysis of the SLC2A1 gene were studied by automated Sanger sequencing and multiplex ligation-dependent probe amplification. Mutations in the SLC2A1 gene were detected in 54 patients (41%) and subsequently in three clinically affected family members. In these 57 patients we identified 49 different mutations, including six multiple exon deletions, six known mutations and 37 novel mutations (13 missense, five nonsense, 13 frame shift, four splice site and two translation initiation mutations). Clinical data were retrospectively collected from referring physicians by means of a questionnaire. Three different phenotypes were recognized: (i) the classical phenotype (84%), subdivided into early-onset (<2 years) (65%) and late-onset (18%); (ii) a non-classical phenotype, with mental retardation and movement disorder, without epilepsy (15%); and (iii) one adult case of glucose transporter-1 deficiency syndrome with minimal symptoms. Recognizing glucose transporter-1 deficiency syndrome is important, since a ketogenic diet was effective in most of the patients with epilepsy (86%) and also reduced movement disorders in 48% of the patients with a classical phenotype and 71% of the patients with a non-classical phenotype. The average delay in diagnosing classical glucose transporter-1 deficiency syndrome was 6.6 years (range 1 month-16 years). Cerebrospinal fluid glucose was below 2.5 mmol/l (range 0.9-2.4 mmol/l) in all patients and cerebrospinal fluid : blood glucose ratio was below 0.50 in all but one patient (range 0.19-0.52). Cerebrospinal fluid lactate was low to normal in all patients. Our relatively large series of 57 patients with glucose transporter-1 deficiency syndrome allowed us to identify correlations between genotype, phenotype and biochemical data. Type of mutation was related to the severity of mental retardation and the presence of complex movement disorders. Cerebrospinal fluid : blood glucose ratio was related to type of mutation and phenotype. In conclusion, a substantial number of the patients with glucose transporter-1 deficiency syndrome do not have epilepsy. Our study demonstrates that a lumbar puncture provides the diagnostic clue to glucose transporter-1 deficiency syndrome and can thereby dramatically reduce diagnostic delay to allow early start of the ketogenic diet.
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PMID:Glucose transporter-1 deficiency syndrome: the expanding clinical and genetic spectrum of a treatable disorder. 2015 7

Myoclonus dystonia (M-D) is a rare genetic movement disorder characterized by a combination of myoclonic jerks and dystonia. It is usually due to mutations in the SGCE gene. We report on a patient with a typical M-D syndrome, but also short stature, microcephaly, and mental retardation. Molecular analysis showed no mutations within the SGCE gene but a microdeletion encompassing the SGCE gene in chromosome region 7q21. Array-CGH analysis showed that the deletion spanned approximately 1.88 Mb. We suggest that M-D plus patients with mental retardation, microcephaly, dysmorphism, or short stature, all frequently associated disorders, should be screened for 7q21 microdeletion. By examining previously published cases of mental retardation associated with pure 7q21 deletions, we identified two distinct regions of respectively 455 and 496 kb that are critical for mental retardation and growth retardation. Among the genes located within these regions, LOC253012, also known as HEPACAM2, is a good candidate for both mental retardation and microcephaly.
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PMID:Myoclonus dystonia plus syndrome due to a novel 7q21 microdeletion. 2042 29

In the International Classification of Sleep Disorders 2nd Edition (ICSD-2), sleep related rhythmic movement disorder (RMD) is classified as a disorder characterized by rhythmic movements of large muscle groups in different parts of the body. These are repetitive, stereotyped, rhythmic motor behaviors that occur predominantly during drowsiness or sleep,and are typically seen in infants and children. Episodes often occur at sleep onset, at any time during the night, and during quiet wakeful activities at a frequency of 0.5-2 sec), lasting <15 min. The prevalence is high in infants (59%), dropping to 5% at the age of 5 years. When persisting to older childhood or beyond, association with mental retardation, autism, or other significant pathology is reported. Few cases in adults of normal intelligence have been reported in the literature. There is a strong association with attention deficit hyperactivity disorder, suggesting a similar pathogenetic mechanism. There is also one adult case report occurring during strictly REM sleep. Mayer et al reported 24 subjects with RMD that persisted into adolescence and adulthood. Twenty of the subjects were adults, and 16 of them had the condition since childhood. Of these 20, 16 had no other sleep disorders (but 2 had a family history of RMD), and 4 had obstructive sleep apnea. This was the first ever report of familial RMD.
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PMID:A multigenerational family with persistent sleep related rhythmic movement disorder (RMD) and insomnia. 2046 26


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