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

Stem cell factor (SCF) promotes the growth of multilineage hematopoietic cells. SCF is a product of the steel (Sl) locus of the mouse, and it is a ligand for the c-kit proto-oncogene receptor. Previous studies have investigated the distribution of SCF mRNA in developing and adult tissues of the rat, including the brain. However, there have been conflicting reports on the distribution of SCF mRNA in adult rat brain. Specially noteworthy was one report of the absence of SCF mRNA in adult hippocampus, while another group reported the presence of that mRNA in the dentate gyrus of the hippocampus. We conducted this study to determine the precise localization of SCF mRNA in adult brain, and were especially interested in determining whether that mRNA is localized in adult hippocampus. We used in situ hybridization histochemistry to demonstrate that the gene encoding SCF is actively expressed in neuron-like cells in various regions of adult rat brain. Our data show that SCF mRNA is present in neuron-like cells in the thalamus, cerebral cortex, cerebellum, and hippocampus, particularly in the dentate gyrus, but also in CA1, CA2, and CA3. We did not localize SCF mRNA in glia-like cells. Dyskeratosis congenita is a severe human disorder, associated with dyskeratosis, anemia, and mental retardation. It has been postulated that dyskeratosis congenita is due to a deficiency in SCF function. It is unknown why patients with dyskeratosis congenita suffer from mental retardation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Localization of stem cell factor mRNA in adult rat hippocampus. 748 32

Down Syndrome (DS) is a major cause of mental retardation and is associated with characteristic well-defined although subtle brain abnormalities, many of which arise after birth, with particular defects in the cortex, hippocampus and cerebellum. The neural cell adhesion molecule DSCAM (Down syndrome cell adhesion molecule) maps to 21q22.2-->q22.3, a region associated with DS mental retardation, and is expressed largely in the neurons of the central and peripheral nervous systems during development. In order to evaluate the contribution of DSCAM to postnatal morphogenetic and cognitive processes, we have analyzed the expression of the mouse DSCAM homolog, Dscam, in the adult mouse brain from 1 through 21 months of age. We have found that Dscam is widely expressed in the brain throughout adult life, with strongest levels in the cortex, the mitral and granular layers of the olfactory bulb, the granule cells of the dentate gyrus and the pyramidal cells of the CA1, CA2 and CA3 regions, the ventroposterior lateral nuclei of the thalamus, and in the Purkinje cells of the cerebellum. Dscam is also expressed ventrally in the adult spinal cord. Given the homology of DSCAM to cell adhesion molecules involved in development and synaptic plasticity, and its demonstrated role in axon guidance, we propose that DSCAM overexpression contributes not only to the structural defects seen in these regions of the DS brain, but also to the defects of learning and memory seen in adults with DS.
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PMID:Down syndrome cell adhesion molecule is conserved in mouse and highly expressed in the adult mouse brain. 1185 73

Cornelia de Lange syndrome (CDLS) is a rare multisystemic malformative syndrome of uncertain etiology characterized by severe psychomotor and mental retardation. Here we report the neuropathological analysis of a 35-year-old patient who displayed the classical clinical symptomatology of CDLS. A congenital dysgenesis of the brain was evident including abnormal convolution patterns of the cerebral gyri, frontal lobe hypoplasia and focal lack of myelination in layers V and VI of the left temporal cortex. In addition, there were vascular scars in the CA2-3 region of the left hippocampus and in the right parietal cortex as well as a few neurofibrillary tangles in the CA fields of the hippocampus and in the entorhinal cortex. In contrast to previous reports, there were no midline cerebral dysgenesis and no ectopic neuron formations in the present case. Neuronal loss and gliosis were also absent in all cortical and subcortical areas. Our observations suggest that the main neurodevelopmental deficits in CDLS occur during the late phase of gestation. Conversely, early neurodegenerative changes are not characteristic of CDLS. In the light of previous studies in younger CDLS patients, the vascular and degenerative lesions observed in the present case may be secondary to his severe congenital heart abnormalities and self-injury behavior, respectively.
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PMID:Neuropathological analysis of an adult case of the Cornelia de Lange syndrome. 1217 20

The rare bone thickening disease osteopetrosis occurs in various forms, one of which is accompanied by renal tubular acidosis (RTA), and is known as Guibaud-Vainsel syndrome or marble brain disease. Clinical manifestations of this autosomal recessive syndrome comprise increased bone density, growth failure, intracerebral calcification, facial dysmorphism, mental retardation, and conductive hearing impairment. The most common cause is carbonic anhydrase II (CAII) deficiency. Several different loss of function mutations in CA2, the gene encoding CAII, have been described. To date, there have been no exceptions to the finding of CAII deficiency in patients with coexistent osteopetrosis and RTA. Most often, the RTA is of mixed proximal and distal type, but kindreds are reported in which either distal or proximal RTA predominates. We report the molecular genetic investigation of two consanguineous kindreds where osteopetrosis and distal RTA (dRTA) were both manifest. One kindred harbours a novel homozygous frameshift alteration in CA2. In the other, CAII levels were normal despite a similar clinical picture, and we excluded defects in CA2. In this kindred, two separate recessive disorders are penetrant, each affecting a different, tissue specific subunit of the vacuolar proton pump (H(+)-ATPase), providing a highly unusual, novel genetic explanation for the coexistence of osteopetrosis and dRTA. The osteopetrosis is the result of a homozygous deletion in TCIRG1, which encodes an osteoclast specific isoform of subunit a of the H(+)-ATPase, while the dRTA is associated with a homozygous mutation in ATP6V1B1, encoding the kidney specific B1 subunit of H(+)-ATPase. This kindred is exceptional firstly because the coinheritance of two rare recessive disorders has created a phenocopy of CAII deficiency, and secondly because these disorders affect two different subunits of the H(+)-ATPase that have opposite effects on bone density, but which have only recently been determined to possess tissue specific isoforms.
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PMID:A phenocopy of CAII deficiency: a novel genetic explanation for inherited infantile osteopetrosis with distal renal tubular acidosis. 1256 20

Symptoms like mental retardation, depression, and anxiety have been observed during aging. Almost similar phenotypes have been evident in patients having haploinsufficiency or mutations in Pax6, a transcriptional regulator. Since Pax6 regulates axon guidance, differentiation of neurons from glia, and neuronal migration, it has been considered as a marker of newly generated neurons. The immunohistochemical analysis of Pax6 positive cells and expression pattern of Pax6 in olfactory lobe, hippocampus, and cerebellum of aging mouse brain have been investigated. The number of Pax6 positive cells and level of Pax6 were reduced progressively in olfactory lobe, cerebellum, and hippocampus from postnatal day-zero (P0) to old age mice. Pax6 positive cells were significantly lower in dentate gyrus, CA1, CA2, and CA3 regions of hippocampus, in mitral cell (MiCe), and internal plexiform (InPl) layers of olfactory lobe, and in granular cell (GrLa), and Purkinje's cell (PuCe) layers of cerebellum from P0 to old age. Thus, modulation in the expression of Pax6 and reduction in Pax6 positive cells show direct association of Pax6 with aging-related neuronal dystrophy.
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PMID:Aging-associated modulation in the expression of Pax6 in mouse brain. 2190 10

Carbonic anhydrase II (CAII) deficiency is an autosomal recessive disorder characterized by renal tubular acidosis, osteopetrosis, recurrent bone fractures, renal stones, growth failure, and mental retardation. Several cases have been reported in Saudi Arabia with homozygous mutations in CA2 consistent with a high degree of consanguinity. We report a case of carbonic anhydrase II deficiency with short stature, mixed renal tubular acidosis, recurrent bone fractures due to trivial trauma, recurrent renal stones and cerebral calcification. This patient was compound heterozygous for a novel CA2 mutation and a previously reported mutation in Arabs.
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PMID:Carbonic anhydrase II deficiency: report of a novel mutation. 2850 78

The interaction of multiple genetic factors, as opposed to monogenic inheritance, has been suspected to play a role in many diseases. This interaction has been described as an oligogenic inheritance model, which may be a useful tool in explaining certain clinical observations. The purpose of this study was to search for novel genetic defects among members of a family with traits that include mental retardation, short stature, osteopetrosis, calcification of basal ganglia, and thinning of the corpus callosum. In the index case (111-4), we identified four homozygous mutations: chromosome 8, intron2 (c.232+1G>A) at CA2 gene; chromosome 15, exon 32 (c.6100C>T) at the SPG11; chromosome 5, exon 11 (c.1015G>A) at the MCCC2; and chromosome 9, exon 9 (C.1193g>t) at the LARP gene. The mutations were confirmed by Sanger sequencing, and both parents were observed to be heterozygous for the four mutations. A moderately affected sister of the index case was homozygous for only three mutations in CA2, LARP, and Mccc2, while a nonaffected sister was heterozygous for three mutations in CA2, LARP, and MCCC2 and negative for SPG11. The clinical features of the two affected sisters can be explained distinctively by each homozygous mutation in an oligogenic pattern of inheritance. This family represents an example of an oligogenic pattern of inheritance of mental retardation, short stature, spastic paraparesis, and osteopetrosis.
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PMID:Potential oligogenic disease of mental retardation, short stature, spastic paraparesis, and osteopetrosis. 3051 Apr 38