Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0085584 (encephalopathy)
 18,178 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pelizaeus-Merzbacher's disease is a progressive encephalopathy with demyelination of the cerebral white matter. The diagnosis can not be made on clinical or biological grounds: pathological investigation is necessary to confirm tigroid demyelination. CT scanning failed to visualize this type of anomaly but detection is now possible with the advent of magnetic resonance imaging (MRI). The authors studied the case of a boy who, at the age of 8 presented with symptoms characteristic of the disease: rotatory nystagmus, progressive encephalopathy, and inherited X-linked recessive traits. Magnetic resonance imaging revealed a high signal in the supra- tentorial white matter and the usual contrast was inverted. The authors believe that MRI can make an important contribution to the diagnosis of the disease.
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PMID:Magnetic resonance imaging in Pelizaeus-Merzbacher disease. 362 26

Deficiency of ornithine transcarbamylase, an enzyme in the urea cycle, results in hyperammonemia. The X-linked recessive inheritance results in neonatal death of affected males but a variable symptomatic pattern in females, with onset of symptoms in childhood. We report the cases of two heterozygous women with onset of severe symptoms (encephalopathy and focal neurologic deficits) in adulthood.
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PMID:Ornithine transcarbamylase deficiency: adult onset of severe symptoms. 382 55

Ornithine transcarbamylase deficiency is an X-linked recessive disorder of urea biosynthesis characterized by recurrent, often fatal, hyperammonemic encephalopathy in affected males; carrier females are usually asymptomatic. We report here the clinical and laboratory findings in five symptomatic heterozygous females with ornithine transcarbamylase deficiency. In each case, the onset of symptoms occurred in the 1st year of life, but diagnosis was delayed by up to 15 years. Symptoms included recurrent vomiting with lethargy (five patients), dietary protein intolerance (five), irritability (four), severe acute encephalopathy (three), ataxia (three), and acute hemiparesis (two). All eventually showed evidence of developmental delay or learning difficulties. Two of the three who experienced severe, acute, hyperammonemic encephalopathy suffered serious, permanent neurologic sequelae. Three of the patients showed decreased ornithine transcarbamylase activity in liver obtained by needle biopsy, and the other two had marked orotic aciduria associated with hyperammonemia. Neuroimaging studies demonstrated persistent abnormal lobar attenuation and abnormal signal on computed tomographic scan and magnetic resonance imaging. All patients showed marked symptomatic improvement on treatment with dietary protein restriction supplemented by pharmacologic measures to increase nonprotein nitrogen excretion. Ornithine transcarbamylase deficiency should be considered in the differential diagnosis of acute or chronic encephalopathy in females at any age.
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PMID:Ornithine transcarbamylase deficiency in females: an often overlooked cause of treatable encephalopathy. 749 56

Although MECP2 was initially identified as the causative gene in classic Rett syndrome (RTT), the gene has now been implicated in several phenotypes that extend well beyond the clinically defined disorder. MECP2 mutations have been found in people with various disorders, including neonatal onset encephalopathy, X-linked recessive mental retardation (MRX), classic and atypical RTT, autism, and Angelman syndrome, as well as mildly affected females and normal carrier females. To make matters more complex, in approximately 20% of classic sporadic RTT cases and more than 50% of affected sister pairs, no mutation in MECP2 has been found. X-chromosome inactivation patterns can clearly affect the phenotypic expression in females, while the effect of the type and position of the mutation is more apparent in the broader phenotype than in RTT. Both males and females are at risk, although an excess of paternally derived mutations are found in most cases of classic RTT. Thus, because of the range of disparate phenotypes, the gene may account for a relatively large portion of mental retardation in the population.
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PMID:The phenotypic consequences of MECP2 mutations extend beyond Rett syndrome. 1211 34

Rett syndrome (RTT) is a severe neurodevelopmental disorder affecting almost exclusively girls. It is currently considered a monogenic X-linked dominant disorder due to mutations in MECP2 gene, encoding the methyl-CpG binding protein 2. A few RTT male cases, resulting from mosaicism for MECP2 mutations, have been reported. Male germline MECP2 mutations cause either severe encephalopathy with death at birth (usually in brothers of classical RTT females) or X-linked recessive mental retardation (XLMR). To date the wide phenotypic heterogeneity associated with MECP2 mutations in females (from classical RTT to healthy carriers) has been explained by differences in X chromosome inactivation. However, conflicting results have been obtained in different studies, with both random and highly skewed X-inactivation reported in healthy carrier females. Consequently it is possible that mechanisms other than X-inactivation play a role in the expressivity of MECP2 mutations. To explain the phenotypic heterogeneity associated with MECP2 mutations we propose a digenic model in which the presence of a "mutated" allele in a second gene, leading to a less functional protein, determines the clinical severity of the MECP2 mutation. The model is supported by the identification of the same mutation in XLMR and RTT cases. The carrier mothers of XLMR families are clinically asymptomatic and present balanced X chromosome inactivation. Therefore the same mutation arising in different genetic backgrounds can cause XLMR in males, remain silent in the carrier females and cause classic RTT in females. MECP2 mutations account for approximately 70-80% of classic RTT cases. MECP2 negative cases might result from mutations in noncoding regions of MECP2 gene. Alternatively, these cases might be due to mutations in other genes (locus heterogeneity). This hypothesis is supported by the identification of several chromosomal rearrangements in MECP2 negative patients with RTT and RTT-like phenotypes. MeCP2 is considered a general transcriptional repressor. However, conditional mouse mutants with selective loss of Mecp2 in the brain develop clinical manifestations similar to RTT, indicating that MECP2 is exclusively required for central nervous system function. The involvement of MeCP2 in methylation-specific transcriptional repression suggests that MECP2 related disorders result from dysregulated gene expression. Studies on gene expression have been performed in mouse and human brains. A relatively small number of gene expression changes were identified. It is possible that MeCP2 causes dysregulation of a very small subset of genes that are not detected with this method of analysis, or that very subtle changes in many genes cause the neuronal phenotype.
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PMID:Rett syndrome: the complex nature of a monogenic disease. 1275 Aug 21

Ornithine transcarbamoylase (OTC) deficiency is the most common hereditary urea cycle disorder. It is an X-linked recessive disorder that usually presents with encephalopathy and hyperammonaemia. We report a 14-month-old female carrier of OTC deficiency, who presented with a history of intermittent vomiting for 5 weeks and irritability and lethargy for 1 week. She was found to be in acute liver failure, with elevated transaminases, coagulopathy and a consistently low urea. Identifying an OTC mutation and ruling out other possible causes of acute hepatic failure confirmed the diagnosis. She was placed on low-protein diet supplemented with essential amino acids, and her liver enzymes, hyperammonaemia and coagulopathy corrected. Three other female patients have been reported with OTC deficiency presenting with severe cryptogenic hepatitis; our patient is unique in that the presentation of her disease was dominated by acute liver failure on a back ground of normal growth and development, no liver enlargement, and mild hyperammonaemia. OTC deficiency should be considered in the differential diagnosis of infants presenting with acute hepatocellular dysfunction, especially in females.
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PMID:Ornithine transcarbamoylase deficiency presenting with acute liver failure. 1680 8

Antidiuretic hormone (ADH), or arginine vasopressin (AVP), is primarily regulated through plasma osmolarity, as well as non-osmotic stimuli including blood volume and stress. Links between water-electrolyte and carbohydrate metabolism have also been recently demonstrated. AVP acts via the intermediary of three types of receptors: V1a, or V1, which exerts vasoconstrictive effects; pituitary gland V1b, or V3, which participates in the secretion of ACTH; and renal V2, which reduces the excretion of pure water by combining with water channels (aquaporin 2). Antidiuresis syndrome is a form of euvolaemic, hypoosmolar hyponatraemia, which is characterised by a negative free water clearance with inappropriate urine osmolality and intracellular hyper-hydration in the absence of renal, adrenal and thyroid insufficiency. Ninety percent of cases of antidiuresis syndrome occur in association with hypersecretion of vasopressin, while vasopressin is undetectable in 10% of cases. Thus the term "antidiuresis syndrome" is more appropriate than the classic name "syndrome of inappropriate ADH secretion" (SIADH). The clinical symptoms, morbidity and mortality of hyponatraemia are related to its severity, as well as to the rapidity of its onset and duration. Even in cases of moderate hyponatraemia that are considered asymptomatic, there is a very high risk of falls due to gait and attention disorders, as well as rhabdomyolysis, which increases the fracture risk. The aetiological diagnosis of hyponatraemia is based on the analysis of calculated or measured plasma osmolality (POsm), as well as blood volume (skin tenting of dehydration, oedema). Hyperglycaemia and hypertriglyceridaemia lead to hyper- and normoosmolar hyponatraemia, respectively. Salt loss of gastrointestinal, renal, cutaneous and sometimes cerebral origin is hypovolaemic, hypoosmolar hyponatraemia (skin tenting), whereas oedema is present with hypervolaemic, hypoosmolar hyponatraemia of heart failure, nephrotic syndrome and cirrhosis. Some endocrinopathies (glucocorticoid deficiency and hypothyroidism) are associated with euvolaemic, hypoosmolar hyponatraemia, which must be distinguished from SIADH. Independent of adrenal insufficiency, isolated hypoaldosteronism can also be accompanied by hypersecretion of vasopressin secondary to hypovolaemia, which responds to mineralocorticoid administration. The causes of SIADH are classic: neoplastic (notably small-cell lung cancer), iatrogenic (particularly psychoactive drugs, chemotherapy), lung and cerebral. Some causes have been recently described: familial hyponatraemia via X-linked recessive disease caused by an activating mutation of the vasopressin 2 receptor; and corticotropin insufficiency related to drug interference between some inhaled glucocorticoids and cytochrome p450 inhibitors, such as the antiretroviral drugs and itraconazole, etc. SIADH in marathon runners exposes them to a risk of hypotonic encephalopathy with fatal cerebral oedema. SIADH treatment is based on water restriction and demeclocycline. V2 receptor antagonists are still not marketed in France. These aquaretics seem effective clinically and biologically, without demonstrated improvement to date of mortality in eu- and hypervolaemic hyponatraemia. Obviously treatment of a corticotropic deficit, even subtle, should not be overlooked, as well as the introduction of fludrocortisone in isolated hypoaldosteronism and discontinuation of iatrogenic drugs.
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PMID:Hyponatremia and antidiuresis syndrome. 2211 69

X-linked recessive myotubular myopathy (XLMTM) is a severe congenital muscle disorder caused by mutations in the MTM1 gene and characterized by severe hypotonia and generalized muscle weakness in affected males. It is generally a fatal disorder during the neonatal period and early infancy. The diagnosis is based on typical histopathological findings on muscle biopsy, combined with suggestive clinical features. We experienced a case of a newborn who required intubation and ventilator care because of profound hypotonia and respiratory difficulty. The preliminary diagnosis at the time of request for retrieval was hypoxic ischemic encephalopathy, but the infant was clinically reevaluated for generalized weakness and muscle atrophy. Muscle biopsies showed variability in fiber size and centrally located nuclei in nearly all the fibers. We detected an MTM1 gene mutation of c.1261-1C>A in the intron 10 region, and diagnosed the neonate with myotubular myopathy. The same mutation was detected in his mother.
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PMID:X-linked recessive myotubular myopathy with MTM1 mutations. 2355 77

Pathogenic CDKL5 variants cause an X-linked dominant infantile epileptic encephalopathy, predominantly in females. This condition is characterized by an early-onset severe mixed seizure disorder. We present a maternally inherited frameshift CDKL5 c.2809_2810insA p.(Cys937Ter) variant in a 13-year-old male with severe intellectual disability and late-onset generalized epilepsy. Interestingly, the variant segregation in the family is consistent with an X-linked recessive inheritance pattern, which has not previously been described with this gene. This variant is expected to result in truncation of some CDKL5 transcripts, which could potentially account for the later seizure onset and atypical inheritance pattern. Though the possibility of this variant not being causal cannot be completely excluded, this case adds to the variability of the documented phenotypic profile and to the debate around the role of C-terminus variants in CDKL5-related disease.
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PMID:A maternally inherited frameshift CDKL5 variant in a male with global developmental delay and late-onset generalized epilepsy. 3062 22

Menkes disease is a rare X-linked recessive disorder caused by impaired copper absorption and transport. Presented here is a case of a 12-week-old male who presented with hypotonia and multiple metaphyseal fractures. Further imaging and workup revealed a diagnosis of Menkes disease. While nonaccidental trauma is a much more common cause of metaphyseal bone fractures, encephalopathy, and subdural hematomas in infants, Menkes syndrome should be considered in the setting of corroborating signs and symptoms, as early diagnosis and treatment can delay progression of the disease.
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PMID:Imaging findings of Menkes disease, a radiographic mimic of abusive trauma. 3119 82


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