Bilateral periventricular nodular heterotopia with mental retardation and frontonasal malformation

So far, sleep researches have been improved by tight collaborations between behavioral and modeling studies. From the novel point of view, we developed the thermoregulatory model of sleep control, which reproduces the well-known features of human sleep-waking cycles. The biphasic daily pattern of sleepiness and the resulting behavior during sleep deprivation are mechanistically interpreted by reducing them into the behavior of the model elements. In addition, a physiological mechanism underlying REM (rapid eye movement sleep) regulation is modelled based on the recent physiological knowledge, which could be a novel explanation instead of the reciprocally interacting model of REM generation (McCarley et al, 1975). Our model successfully produces the limit cycle of REM-related neuronal activities.     

Evidence for nodular epileptogenicity and gender differences in periventricular nodular heterotopia

The new synthetic oleanane triterpenoid 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid (CDDO) is a potent, multifunctional molecule. It induces monocytic differentiation of human myeloid leukemia cells and adipogenic differentiation of mouse 3T3-L1 fibroblasts and enhances the neuronal differentiation of rat PC12 pheochromocytoma cells caused by nerve growth factor. CDDO inhibits proliferation of many human tumor cell lines, including those derived from estrogen receptor-positive and -negative breast carcinomas, myeloid leukemias, and several carcinomas bearing a Smad4 mutation. Furthermore, it suppresses the abilities of various inflammatory cytokines, such as IFN-gamma, interleukin-1, and tumor necrosis factor-alpha, to induce de novo formation of the enzymes inducible nitric oxide synthase (iNos) and inducible cyclooxygenase (COX-2) in mouse peritoneal macrophages, rat brain microglia, and human colon fibroblasts. CDDO will also protect rat brain hippocampal neurons from cell death induced by beta-amyloid. The above activities have been found at concentrations ranging from 10(-6) to 10(-9) M in cell culture, and these results suggest that CDDO needs further study in vivo, for either chemoprevention or chemotherapy of malignancy as well as for neuroprotection.     

Oligophrenin-1 encodes a rhoGAP protein involved in X-linked mental retardation

Primary or nonspecific X-linked mental retardation (MRX) is a heterogeneous condition in which affected patients do not have any distinctive clinical or biochemical features in common apart from cognitive impairment. Although it is present in approximately 0.15-0.3% of males, most of the genetic defects associated with MRX, which may involve more than ten different genes, remain unknown. Here we report the characterization of a new gene on the long arm of the X-chromosome (position Xq12) and the identification in unrelated individuals of different mutations that are predicted to cause a loss of function. This gene is highly expressed in fetal brain and encodes a protein of relative molecular mass 91K, named oligophrenin-1, which contains a domain typical of a Rho-GTPase-activating protein (rhoGAP). By enhancing their GTPase activity, GAP proteins inactivate small Rho and Ras proteins, so inactivation of rhoGAP proteins might cause constitutive activation of their GTPase targets. Such activation is known to affect cell migration and outgrowth of axons and dendrites in vivo. Our results demonstrate an association between cognitive impairment and a defect in a signalling pathway that depends on a Ras-like GTPase.     

Non-specific X-linked semidominant mental retardation by mutations in a Rab GDP-dissociation inhibitor

Non-specific X-linked mental retardation (MRX) is a very common disorder which affects approximately 1 in 600 males. Despite this high frequency, little is known about the molecular defects underlying this disorder, mainly because of the clinical and genetic heterogeneity which is evident from linkage studies. Recently, a collaborative study using the candidate gene approach demonstrated the presence of mutations in GDIalpha, a Rab GDP-dissociation inhibitor encoded by a gene localized in Xq28, associated with non-specific mental retardation. GDIalpha is mainly a brain-specific protein that plays a critical role in the recycling of Rab GTPases involved in membrane vesicular transport. The study presented here was designed to assess the prevalence of mutations in the GDIalpha in mentally retarded patients and to discuss the clinical phenotypes observed in affected individuals. Mutation screening of the whole coding region of the GDIalpha gene, using a combination of denaturing gradient gel electrophoresis and direct sequencing, was carried out in 164 patients found negative for expansions across the FRAXA GCC repeat. In addition to the nonsense mutation recently reported in MRX48, we have identified a novel missense mutation in exon 11 of the GDIalpha gene in one familial form of non-specific mental retardation. In this family (family R), all affected males show moderate to severe mental retardation, and the X-linked semidominant inheritance is strongly suggested by the severe phenotypes in males with respect to mildly affected females or unaffected obligatory carriers. This study showed that the prevalence of GDIalpha mutations in non-specific mental retardation could be estimated to be 0.5-1%, and molecular diagnosis and genetic counselling in some cases of non-specific mental handicap can now be provided.     

Developmental delay, expressive aphasia, hypotonia and dysmorphism in two brothers: an X-linked mental retardation syndrome?

Five 72-86 years old women complaining of vaginal bleeding and genital discomfort during the last three weeks. Physical examination show an urethral mass of 1 cm diameter with a black, hard and painful area inside. Blood test was normal, and clinical diagnosis of caruncle urethral thrombosis was done. Topic treatment was develop with good results. We discuss the pathogenic and clinical presentation as well as the treatment of this unusual lesion.     

X-linked mental retardation with a fragile site in Xq and an inversion of chromosome no. 9

The second black male with X-linked mental retardation and a fragile site at Xq27 was ascertained by screening for macroorchidism. GTG banding revealed the presence of an inv(9)(p13q21). This inversion is thought to be a chance occurrence and is probably of no clinical significance. More cases having a marker Xq and a chromosome abnormality are expected; some of these abnormalities will be clinically significant.     

Fragile X syndrome and fragile XE mental retardation

There are two forms of mental handicap associated with fragile sites on the end of the long arm of the X chromosome. The well known common disorder Fragile X syndrome is associated with FRAXA and a rare non-specific form of mental handicap is associated with FRAXE. The cytogenetics of these fragile sites is considered. For Fragile X syndrome details are given of the molecular genetics, inheritance patterns, genetic counselling, methods for diagnosis of index cases, carrier detection and prenatal diagnosis. Series of prenatal diagnoses are briefly reviewed and technical and biological problems associated with this procedure are considered. Prenatal diagnosis of Fragile X syndrome using molecular genetic techniques is now a well established procedure, with the only significant problem being the inability to accurately predict phenotype in female fetuses with full mutations. Few prenatal diagnoses of Fragile XE non-specific mental retardation have been recorded. In principle the technical aspects of such a prenatal diagnosis should be little different from those for Fragile X syndrome. Incomplete knowledge of the phenotypic effect of the full mutation in males and females would make phenotypic prediction for any fetus shown to have such a mutation very difficult. At this stage all that could be determined with precision is that the mutation was present or absent in the fetus. Possible consequences of this are discussed.     

Olfactory identification deficits in Down's syndrome and idiopathic mental retardation

We investigated olfactory identification in children and adults with Down's syndrome (DS) and idiopathic mental retardation (IMR) and in age-matched normal controls (NC). Identification was assessed with a four alternative-forced-choice task modified from the University of Pennsylvania Smell Identification Test (M-UPSIT) and a yes/no task yielding measures of discrimination and response bias for the same stimulus material. Control tactile identification tasks were also administered. Results were that odor identification performance on both tasks was specifically impaired in DS compared to IMR and NC. Accuracy of identification on the M-UPSIT correlated inversely with age in DS only. When uncertain, DS and IMR subjects guessed "yes" more often than "no" on the Yes/No task (liberal decision bias) and guessed the last response alternative on the M-UPSIT (recent position bias), whereas the normal subjects had neutral decision bias on the Yes/No task and matched the objective position presentation probabilities on the M-UPSIT. Decision bias correlated with accuracy of identification in both tasks for the DS subjects only.     

Subcortical laminal heterotopia and lissencephaly: cerebral malformations of X-linked inheritance

The effects of single and repeated administration of amphetamine (5 mg/kg, i.p., twice a day for 14 days) on the thyrotropin-releasing hormone (TRH) level, release and receptors in the rat striatum and nucleus accumbens were evaluated. Both treatments decreased the TRH level in those structures at 2 h after the drug injection. These effects were accompanied with elevation of the basal release of TRH from the nucleus accumbens and striatal slices at the same time point, whereas the stimulated (K+, 56 mM) TRH release was attenuated following repeated amphetamine administration. Acute amphetamine had no effect on the density and affinity of TRH receptors. Repeated amphetamine increased the Bmax of TRH receptors in the striatum (by ca 49%) and nucleus accumbens (by ca 38%) at 2 h after the last drug injection. At 72 h after the last amphetamine administration, the Bmax of the TRH receptor in the striatum was still elevated (by ca 42%), whereas in the nucleus accumbens it returned to control level. No changes in the affinity of TRH receptors following repeated amphetamine were found. The obtained results indicate that repeated amphetamine evokes long- and short-term up-regulation of TRH receptors in the rat striatum and nucleus accumbens, respectively. Furthermore, it is suggested that these changes may be an adaptive response to the amphetamine-induced alterations in the TRH tissue level and release.     

Haspeslagh syndrome without severe mental retardation and pterygia?

Male infertility is a well recognised problem following spinal cord injury. The techniques of vibration induced ejaculation and transrectal electroejaculation have significantly increased the likelihood of sperm retrieval in spinal cord injured males; however, the reproductive capacity remains markedly reduced due to poor semen quality. The Spinal Injuries Unit at Royal North Shore Hospital has developed a programme to achieve seminal emission and enhance fertility. This study analysed the results of the first sample obtained at stimulation in 70 spinal cord injured males with respect to procedure performed, neurological level, completeness of lesion, bladder management, infection, age and duration since injury. Our study demonstrated that bladder management and neurological level were significant factors affecting the presence of motile sperm. Individuals managing their neuropathic bladder by catheter (intermittent self-catheterisation, indwelling urethral or suprapubic catheter) had significantly enhanced semen quality compared to those voiding by reflex or straining. Differences were also noted within the catheter group itself with intermittent self-catheterisation achieving a higher percentage of motile sperm present.     

The inv dup(15) syndrome: a clinically recognizable syndrome with altered behavior, mental retardation, and epilepsy

The most common of the heterogeneous group of the extra structurally abnormal chromosomes (ESACs) is the inv dup(15), whose presence results in tetrasomy 15p and partial tetrasomy 15q. Inv dup(15), containing the Prader-Willi/Angelman syndrome (PWS/AS) region, are constantly associated with phenotypic abnormalities and mental retardation. We report on four additional patients with inv dup(15), whose behavioral pattern, and neurologic and physical findings further delineate the phenotype of this neurogenetic syndrome. We also provide FISH analyses on chromosomes of the observed ESACs and discuss the role of a number of genes located within the tetrasomic region.     

X-linked hydrocephalus, with aqueductal stenosis, mental retardation, and adduction-flexion deformity of the thumbs. Report of a family

A new family is reported of a Bickers-Adams-Edwards syndrome. This family has been studied up to three generations. Two female carriers are known. Among the six male children who are affected, four are severely mentally retarded, have spasticity of the legs, and survived with a mild macrocephaly, and two show a more severe and rapid progression of head enlargement. A partial aqueductal stenosis, with remarkable ventricular dilatation, has been demonstrated by pneumoence-phalography in three boys. A deformity of the thumbs links these six children together. One of them has been treated by a ventriculoperitoneal shunt, when 18 months old, without any improvement in the neurological condition. The mental deficiency is much more severe than could be expected from the degree of hydrocephalus, at least as estimated clinically by the macrocephaly. Hydrocephalus is precocious, and the ventricular dilatation very advanced when seen by PEG studies. Recognition of the female carriers is not possible.     

Association of Duane anomaly with mental retardation, cardiac and urinary tract abnormalities: a new autosomal recessive condition?

The authors report on a child in which the occurrence of cardiac defect, urinary tract anomaly, and Duane anomaly was associated with mental retardation. The parents were first cousins. The index case was a 3-year-old girl referred for mental retardation. Auricular septal defect was diagnosed at birth. She was surgically treated for bilateral vesico-ureteral reflux at 2 years of age. At examination, she had a mild facial dysmorphism, microcephaly, spastic paraplegia and Duane anomaly. The Duane anomaly may occur in association with various partly overlapping syndromes that may be part of the same clinical spectrum, as the cervico-oculo-acoustic syndrome, the cat eye syndrome and syndromes inherited in an autosomal dominant fashion: the acro-reno-ocular syndrome and the Okihiro syndrome. Their patient seems to have a different condition from all of these previously reported syndromes associated with the Duane anomaly. Their suggest that this condition is best described as a new syndrome.     

Four sibs with dislocated elbows, bowed tibiae, scoliosis, deafness, cataract, microcephaly, and mental retardation: a new MCA/MR syndrome

We report four sibs with an MCA/MR syndrome whose parents were first cousins. The sibs had mental retardation, microcephaly, hearing problems, cataract, and multiple osseous malformations, such as dislocated elbows, bowed tibiae, and scoliosis. Review of published reports and the use of the London Dysmorphology Database suggest that this family presents a new syndrome.     

Implicit and explicit memory in individuals with mental retardation

Students with and without mental retardation from three age groups were compared on implicit and explicit memory tasks. Consistent with previous research on intelligence-related differences in controlled and automatic processes, students without mental retardation performed better than those with mental retardation on the explicit memory task, but there was no difference between groups on the implicit memory task. For both groups implicit and explicit memory increased from age 6 to 8 to age 10 to 12, but did not significantly increase to age 15 to 17. Because implicit memory appears to be a relative strength for students with mental retardation, we suggest further exploration into broader types of implicit processes that may be useful in training situations.     

Rapid immunoblot and kinase assay tests for a syndromal form of X linked mental retardation: Coffin-Lowry syndrome

Coffin-Lowry syndrome (CLS) is a syndromal form of X linked mental retardation, in which some associated facial, hand, and skeletal abnormalities are diagnostic features. Accurate diagnosis, critical for genetic counselling, is often difficult, especially in early childhood. We have recently shown that Coffin-Lowry syndrome is caused by mutations in the gene encoding RSK2, a growth factor regulated protein kinase. RSK2 mutations are very heterogeneous and most of them lead to premature termination of translation or to loss of phosphotransferase activity or both. In the present study, we have evaluated immunoblot and RSK2 kinase assays as a rapid and simple diagnostic test for CLS, using cultured lymphoblastoid or fibroblast cell lines. Western blot analysis failed to detect RSK2 in six patients, suggesting the presence of truncated proteins in these patients. This conclusion was confirmed in four patients, in whom the causative mutations, all leading to premature termination of translation, were identified. Of four patients showing a normal amount of RSK2 protein on western blot and tested for RSK2 phosphotransferase activity, one had a dramatically impaired activity. Analysis of the RSK2 cDNA sequence in this patient showed a mutation of a putative phosphorylation site that would be critical for RSK2 activity. Preliminary results show that, at least, the western blot protocol can be successfully applied to lymphocyte protein extracts prepared directly from blood samples. These assays promise to become important diagnostic tools for CLS, particularly with regard to very young patients with no family history of the condition.     

Psychology in mental retardation: Past and present.

"For purposes of 'before-and-after' comparisons, the membership Directory of the American Association on Mental Deficiency (AAMD, 1952, 1962) was examined. The tabulations show that in 1952, 26% of AAMD psychology members were qualified at the doctoral level. By 1962, 43% were so qualified." Psychologists interested in mental retardation have tended to move "away from the public institutions and clinics, and toward private and municipal services. In 1952, 18% of the psychology membership of the AAMD was engaged in some form and level of full administrative activity. By 1962 it had increased to 21%. During the past decade the memberships in the AAMD psychology division has more than doubled. Yet, in 1952, 21% of all AAMD members were listed as psychologists, whereas by 1962 only 13% were so listed." A table summarizing psychological services to mental retardation in 1952 and 1962 is presented. (PsycINFO Database Record (c) 2010 APA, all rights reserved)