Rett Syndrome
Methyl-CpG-Binding Protein 2
X Chromosome Inactivation
Chromosomal Proteins, Non-Histone
Mutation
Gestalt Theory
Spasms, Infantile
Play Therapy
Disease Models, Animal
Phenotype
Repressor Proteins
Autistic Disorder
Down Syndrome
Dosage Compensation, Genetic
Metabolic Syndrome X
Chromosomes, Human, X
Intellectual Disability
Prolonged QT interval in Rett syndrome. (1/392)
Rett syndrome is a severe neurodevelopmental disorder of unknown aetiology. A prolonged QT interval has been described previously in patients with Rett syndrome. To investigate QT prolongation and the presence of cardiac tachyarrhythmias in Rett syndrome electrocardiography and 24 hour Holter monitoring were performed prospectively in a cohort of 34 girls with Rett syndrome. The corrected QT value was prolonged in nine patients. Compared with a group of healthy controls of a similar age range, the patients with Rett syndrome had significantly longer corrected QT values. Clinical severity was not a predictor for prolonged QT intervals in the Rett syndrome cohort. The prolonged QT syndrome is a serious and potentially lethal cardiac disorder and should be considered in all girls with Rett syndrome. (+info)Congenital variant Rett syndrome in a girl with terminal deletion of chromosome 3p. (2/392)
A girl fulfilling four/five of six inclusion criteria and eight/nine of 11 supportive criteria for atypical Rett syndrome had a cytogenetic deletion of chromosome 3p, del(3)(pter-->3p25.1 approximately 25.2). The deletion was situated on the maternally derived chromosome and by molecular analysis the deletion breakpoint was shown to be between DNA markers D3S3589 and D3S1263. (+info)Developmental aspects of cerebrospinal fluid levels of beta-phenylethylamine and it's role in pediatric neurological disorders. (3/392)
To clarify the role of beta-phenylethylamine (PEA) in pediatric neurological disorders, we have measured the cerebrospinal fluid (CSF) levels of PEA in 12 children with aseptic meningitis--6 were in the acute phase and the other 6 were in the recovery phase--and 5 children with Rett Syndrome (RS). The findings were compared with those obtained from 13 age-matched children with leukemia as child controls and from 10 adults patients without any neurological symptoms and signs as control. In the control group, the CSF PEA level was negatively correlated with age until 200 months (17 years) old. The mean PEA levels in meningitis and RS were significantly lower than that of child controls (p < 0.03). The alteration in the CSF levels of PEA may be related to transient changes in the dopaminergic tone in aseptic meningitis and neurological impairment, especially in the dopaminergic neurons in RS. (+info)Rett syndrome and beyond: recurrent spontaneous and familial MECP2 mutations at CpG hotspots. (4/392)
Rett syndrome (RTT) is a neurodevelopmental disorder characterized by loss of acquired skills after a period of normal development in infant girls. The responsible gene, encoding methyl-CpG binding protein 2 (MeCP2), was recently discovered. Here we explore the spectrum of phenotypes resulting from MECP2 mutations. Both nonsense (R168X and R255X) and missense (R106W and R306C) mutations have been found, with multiple recurrences. R168X mutations were identified in six unrelated sporadic cases, as well as in two affected sisters and their normal mother. The missense mutations were de novo and affect conserved domains of MeCP2. All of the nucleotide substitutions involve C-->T transitions at CpG hotspots. A single nucleotide deletion, at codon 137, that creates a L138X stop codon within the methyl-binding domain was found in an individual with features of RTT and incontinentia pigmenti. An 806delG deletion causing a V288X stop in the transcription-repression domain was identified in a woman with motor-coordination problems, mild learning disability, and skewed X inactivation; in her sister and daughter, who were affected with classic RTT; and in her hemizygous son, who died from congenital encephalopathy. Thus, some males with RTT-causing MECP2 mutations may survive to birth, and female heterozygotes with favorably skewed X-inactivation patterns may have little or no involvement. Therefore, MECP2 mutations are not limited to RTT and may be implicated in a much broader phenotypic spectrum. (+info)Methylation moves into medicine. (5/392)
Two human genetic diseases have recently been shown to be due to mutations in genes encoding proteins involved in DNA methylation. The phenotypes of these two diseases are surprisingly distinct from each other and provide insights into the functions of DNA methylation in mammals. (+info)Mutation screening in Rett syndrome patients. (6/392)
Rett syndrome (RTT) was first described in 1966. Its biological and genetic foundations were not clear until recently when Amir et al reported that mutations in the MECP2 gene were detected in around 50% of RTT patients. In this study, we have screened the MECP2 gene for mutations in our RTT material, including nine familial cases (19 Rett girls) and 59 sporadic cases. A total of 27 sporadic RTT patients were found to have mutations in the MECP2 gene, but no mutations were identified in our RTT families. In order to address the possibility of further X chromosomal or autosomal genetic factors in RTT, we evaluated six candidate genes for RTT selected on clinical, pathological, and genetic grounds: UBE1 (human ubiquitin activating enzyme E1, located in chromosome Xp11.23), UBE2I (ubiquitin conjugating enzyme E2I, homologous to yeast UBC9, chromosome 16p13.3), GdX (ubiquitin-like protein, chromosome Xq28), SOX3 (SRY related HMG box gene 3, chromosome Xq26-q27), GABRA3 (gamma-aminobutyric acid type A receptor alpha3 subunit, chromosome Xq28), and CDR2 (cerebellar degeneration related autoantigen 2, chromosome 16p12-p13.1). No mutations were detected in the coding regions of these six genes in 10 affected subjects and, therefore, alterations in the amino acid sequences of the encoded proteins can be excluded as having a causative role in RTT. Furthermore, gene expression of MECP2, GdX, GABRA3, and L1CAM (L1 cell adhesion molecule) was also investigated by in situ hybridisation. No gross differences were observed in neurones of several brain regions between normal controls and Rett patients. (+info)Long-read sequence analysis of the MECP2 gene in Rett syndrome patients: correlation of disease severity with mutation type and location. (7/392)
Mutations in the methyl-CpG-binding protein gene MECP2 at Xq28 cause Rett syndrome (RTT), an X-linked dominant neurodevelopmental disorder characterized by a period of stagnation followed by regression in the development of young girls. Mutations were sought in MECP2 in 48 females with classical sporadic RTT, seven families with possible familial RTT and five sporadic females with features suggestive, but not diagnostic of RTT. Long distance PCR coupled with long-read direct sequencing was employed to sequence the entire MECP2 gene coding region in all cases. Mutations were identified in 44/55 (80%) unrelated classical sporadic and familial RTT patients, but only 1/5 (20%) sporadic cases with suggestive but non-diagnostic features of RTT. Twenty-one different mutations were identified (12 missense, four nonsense and five frame-shift mutations); 14 of these were novel. All missense mutations were located either in the methyl-CpG-binding domain or in the transcription repression domain. Nine recurrent mutations were characterized in a total of 33 unrelated cases (73% of all cases with MECP2 mutations). Significantly milder disease was noted in patients carrying missense mutations as compared with those with truncating mutations ( P = 0. 0023), and milder disease was associated with late as compared with early truncating mutations ( P = 0.0190). (+info)Rett syndrome: analysis of MECP2 and clinical characterization of 31 patients. (8/392)
Only recently have mutations in MECP2 been found to be a cause of Rett Syndrome (RTT), a neuro-developmental disorder characterized by mental retardation, loss of expressive speech, deceleration of head growth and loss of acquired skills that almost exclusively affects females. We analysed the MECP2 gene in 31 patients diagnosed with RTT. Sequencing of the coding region and the splice sites revealed mutations in 24 females (77.40%). However, no abnormalities were detected in any of the parents that were available for investigation. Eleven mutations have not been described previously. Confirming two earlier studies, we found that most mutations are truncating and only a few of them are missense mutations. Several females carrying the same mutation display different phenotypes indicating that factors other than the type or position of mutations influence the severity of RTT. Four females with RTT variants were included in the study. Three of these presented with preserved speech while the fourth patient with congenital RTT lacked the initial period of normal development. Detection of mutations in these cases reveals that they are indeed variants of RTT. They represent the mild and the severe extremes of RTT. CONCLUSIONS: mutations in MECP2 seem to be the main cause for RTT and can be expected to be found in approximately 77% of patients that fulfil the criteria for RTT. Therefore analysis of MECP2 should be performed if RTT is suspected. Three mutation hotspots (T158M, R168X and R255X) were confirmed and a further one (R270X) newly identified. We recommend screening for these mutations before analysing the coding region. (+info)Rett Syndrome is a rare, progressive neurodevelopmental disorder that almost exclusively affects females. It is caused by mutations in the MECP2 gene, which provides instructions for making a protein essential for normal brain function. The symptoms of Rett Syndrome typically appear after a period of apparently normal development and can include:
1. Loss of purposeful hand skills, replaced with repetitive, stereotyped movements such as hand wringing or washing
2. Slowed growth and reduced body weight
3. Impaired speech and language skills, although many individuals can understand complex commands
4. Breathing difficulties, including hyperventilation, apnea (breath holding), and air swallowing
5. Impaired muscle tone, which can range from too loose to too rigid
6. Scoliosis or other spinal deformities
7. Seizures
8. Sleep disturbances
9. Anxiety and gastrointestinal issues
The progression of Rett Syndrome varies among individuals, but most require assistance with daily living activities. Despite the challenges associated with this disorder, many individuals with Rett Syndrome live into middle age or beyond.
Methyl-CpG-Binding Protein 2 (MeCP2) is a protein that binds to methylated DNA at symmetric CpG sites and plays a crucial role in the regulation of gene expression. MeCP2 is involved in various cellular processes, including chromatin organization, transcriptional repression, and neurological development. Mutations in the MECP2 gene have been associated with several neurodevelopmental disorders, most notably Rett syndrome, a severe X-linked genetic disorder that primarily affects girls. The MeCP2 protein is highly expressed in brain cells, particularly in neurons, where it helps to maintain the balance between methylated and unmethylated DNA, thereby ensuring proper gene expression and neural function.
A syndrome, in medical terms, is a set of symptoms that collectively indicate or characterize a disease, disorder, or underlying pathological process. It's essentially a collection of signs and/or symptoms that frequently occur together and can suggest a particular cause or condition, even though the exact physiological mechanisms might not be fully understood.
For example, Down syndrome is characterized by specific physical features, cognitive delays, and other developmental issues resulting from an extra copy of chromosome 21. Similarly, metabolic syndromes like diabetes mellitus type 2 involve a group of risk factors such as obesity, high blood pressure, high blood sugar, and abnormal cholesterol or triglyceride levels that collectively increase the risk of heart disease, stroke, and diabetes.
It's important to note that a syndrome is not a specific diagnosis; rather, it's a pattern of symptoms that can help guide further diagnostic evaluation and management.
X chromosome inactivation (XCI) is a process that occurs in females of mammalian species, including humans, to compensate for the difference in gene dosage between the sexes. Females have two X chromosomes, while males have one X and one Y chromosome. To prevent females from having twice as many X-linked genes expressed as males, one of the two X chromosomes in each female cell is randomly inactivated during early embryonic development.
XCI results in the formation of a condensed and transcriptionally inactive structure called a Barr body, which can be observed in the nucleus of female cells. This process ensures that females express similar levels of X-linked genes as males, maintaining a balanced gene dosage. The choice of which X chromosome is inactivated (maternal or paternal) is random and occurs independently in each cell, leading to a mosaic expression pattern of X-linked genes in different cells and tissues of the female body.
Chromosomal proteins, non-histone, are a diverse group of proteins that are associated with chromatin, the complex of DNA and histone proteins, but do not have the characteristic structure of histones. These proteins play important roles in various nuclear processes such as DNA replication, transcription, repair, recombination, and chromosome condensation and segregation during cell division. They can be broadly classified into several categories based on their functions, including architectural proteins, enzymes, transcription factors, and structural proteins. Examples of non-histone chromosomal proteins include high mobility group (HMG) proteins, poly(ADP-ribose) polymerases (PARPs), and condensins.
A mutation is a permanent change in the DNA sequence of an organism's genome. Mutations can occur spontaneously or be caused by environmental factors such as exposure to radiation, chemicals, or viruses. They may have various effects on the organism, ranging from benign to harmful, depending on where they occur and whether they alter the function of essential proteins. In some cases, mutations can increase an individual's susceptibility to certain diseases or disorders, while in others, they may confer a survival advantage. Mutations are the driving force behind evolution, as they introduce new genetic variability into populations, which can then be acted upon by natural selection.
I'm sorry for any confusion, but "Gestalt Theory" is actually a concept in psychology, not medicine. It is a theory of perception that describes the way we organize visual elements into groups or unified wholes rather than processing them as individual parts. The term "Gestalt" is German for "form" or "shape."
In medical/healthcare fields, you might hear about Gestalt principles being used in areas like physical therapy, occupational therapy, or counseling to help patients make sense of their experiences or perceptions, but the theory itself is a concept from psychology.
Infantile spasms, also known as West syndrome, is a rare but serious type of epilepsy that affects infants typically between 4-8 months of age. The spasms are characterized by sudden, brief, and frequent muscle jerks or contractions, often involving the neck, trunk, and arms. These spasms usually occur in clusters and may cause the infant to bend forward or stretch out. Infantile spasms can be a symptom of various underlying neurological conditions and are often associated with developmental delays and regression. Early recognition and treatment are crucial for improving outcomes.
Play therapy is not typically defined in the context of medical terminology, but it is a well-established form of psychotherapy that primarily uses play as a means of helping children communicate their thoughts, feelings, and experiences, even those that are difficult or painful to express. The Association for Play Therapy defines play therapy as "the systematic use of a theoretical model to establish an interpersonal process wherein trained play therapists use the therapeutic powers of play to help clients prevent or resolve psychosocial difficulties and achieve optimal growth and development."
Play therapists create a safe, comfortable environment where children can express themselves through various forms of play, such as toys, games, art supplies, sand trays, and other materials. The therapist observes and engages in the child's play, helping them process their experiences, develop coping skills, improve self-esteem, and enhance social and emotional growth. Play therapy can be an effective intervention for children facing a wide range of issues, including trauma, anxiety, depression, behavioral problems, and developmental challenges.
Animal disease models are specialized animals, typically rodents such as mice or rats, that have been genetically engineered or exposed to certain conditions to develop symptoms and physiological changes similar to those seen in human diseases. These models are used in medical research to study the pathophysiology of diseases, identify potential therapeutic targets, test drug efficacy and safety, and understand disease mechanisms.
The genetic modifications can include knockout or knock-in mutations, transgenic expression of specific genes, or RNA interference techniques. The animals may also be exposed to environmental factors such as chemicals, radiation, or infectious agents to induce the disease state.
Examples of animal disease models include:
1. Mouse models of cancer: Genetically engineered mice that develop various types of tumors, allowing researchers to study cancer initiation, progression, and metastasis.
2. Alzheimer's disease models: Transgenic mice expressing mutant human genes associated with Alzheimer's disease, which exhibit amyloid plaque formation and cognitive decline.
3. Diabetes models: Obese and diabetic mouse strains like the NOD (non-obese diabetic) or db/db mice, used to study the development of type 1 and type 2 diabetes, respectively.
4. Cardiovascular disease models: Atherosclerosis-prone mice, such as ApoE-deficient or LDLR-deficient mice, that develop plaque buildup in their arteries when fed a high-fat diet.
5. Inflammatory bowel disease models: Mice with genetic mutations affecting intestinal barrier function and immune response, such as IL-10 knockout or SAMP1/YitFc mice, which develop colitis.
Animal disease models are essential tools in preclinical research, but it is important to recognize their limitations. Differences between species can affect the translatability of results from animal studies to human patients. Therefore, researchers must carefully consider the choice of model and interpret findings cautiously when applying them to human diseases.
A phenotype is the physical or biochemical expression of an organism's genes, or the observable traits and characteristics resulting from the interaction of its genetic constitution (genotype) with environmental factors. These characteristics can include appearance, development, behavior, and resistance to disease, among others. Phenotypes can vary widely, even among individuals with identical genotypes, due to differences in environmental influences, gene expression, and genetic interactions.
Repressor proteins are a type of regulatory protein in molecular biology that suppress the transcription of specific genes into messenger RNA (mRNA) by binding to DNA. They function as part of gene regulation processes, often working in conjunction with an operator region and a promoter region within the DNA molecule. Repressor proteins can be activated or deactivated by various signals, allowing for precise control over gene expression in response to changing cellular conditions.
There are two main types of repressor proteins:
1. DNA-binding repressors: These directly bind to specific DNA sequences (operator regions) near the target gene and prevent RNA polymerase from transcribing the gene into mRNA.
2. Allosteric repressors: These bind to effector molecules, which then cause a conformational change in the repressor protein, enabling it to bind to DNA and inhibit transcription.
Repressor proteins play crucial roles in various biological processes, such as development, metabolism, and stress response, by controlling gene expression patterns in cells.
Autistic Disorder, also known as Autism or Classic Autism, is a neurodevelopmental disorder that affects communication and behavior. It is characterized by:
1. Persistent deficits in social communication and social interaction across multiple contexts, including:
* Deficits in social-emotional reciprocity;
* Deficits in nonverbal communicative behaviors used for social interaction;
* Deficits in developing, maintaining, and understanding relationships.
2. Restricted, repetitive patterns of behavior, interests, or activities, as manifested by at least two of the following:
* Stereotyped or repetitive motor movements, use of objects, or speech;
* Insistence on sameness, inflexible adherence to routines, or ritualized patterns of verbal or nonverbal behavior;
* Highly restricted, fixated interests that are abnormal in intensity or focus;
* Hyper- or hyporeactivity to sensory input or unusual interest in sensory aspects of the environment.
3. Symptoms must be present in the early developmental period (but may not become fully manifest until social demands exceed limited capacities) and limit or impair everyday functioning.
4. Symptoms do not occur exclusively during the course of a schizophrenia spectrum disorder or other psychotic disorders.
Autistic Disorder is part of the autism spectrum disorders (ASDs), which also include Asperger's Syndrome and Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS). The current diagnostic term for this category of conditions, according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), is Autism Spectrum Disorder.
Down syndrome is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is characterized by intellectual and developmental disabilities, distinctive facial features, and sometimes physical growth delays and health problems. The condition affects approximately one in every 700 babies born in the United States.
Individuals with Down syndrome have varying degrees of cognitive impairment, ranging from mild to moderate or severe. They may also have delayed development, including late walking and talking, and may require additional support and education services throughout their lives.
People with Down syndrome are at increased risk for certain health conditions, such as congenital heart defects, respiratory infections, hearing loss, vision problems, gastrointestinal issues, and thyroid disorders. However, many individuals with Down syndrome live healthy and fulfilling lives with appropriate medical care and support.
The condition is named after John Langdon Down, an English physician who first described the syndrome in 1866.
Genetic dosage compensation is a process that evens out the effects of genes on an organism's phenotype (observable traits), even when there are differences in the number of copies of those genes present. This is especially important in cases where sex chromosomes are involved, as males and females often have different numbers of sex chromosomes.
In many species, including humans, females have two X chromosomes, while males have one X and one Y chromosome. To compensate for the difference in dosage, one of the female's X chromosomes is randomly inactivated during early embryonic development, resulting in each cell having only one active X chromosome, regardless of sex. This process ensures that both males and females have similar levels of gene expression from their X chromosomes and helps to prevent an imbalance in gene dosage between the sexes.
Defects in dosage compensation can lead to various genetic disorders, such as Turner syndrome (where a female has only one X chromosome) or Klinefelter syndrome (where a male has two or more X chromosomes). These conditions can result in developmental abnormalities and health issues due to the imbalance in gene dosage.
Metabolic syndrome, also known as Syndrome X, is a cluster of conditions that increase the risk of heart disease, stroke, and diabetes. It is not a single disease but a group of risk factors that often co-occur. According to the American Heart Association and the National Heart, Lung, and Blood Institute, a person has metabolic syndrome if they have any three of the following five conditions:
1. Abdominal obesity (waist circumference of 40 inches or more in men, and 35 inches or more in women)
2. Triglyceride level of 150 milligrams per deciliter of blood (mg/dL) or greater
3. HDL cholesterol level of less than 40 mg/dL in men or less than 50 mg/dL in women
4. Systolic blood pressure of 130 millimeters of mercury (mmHg) or greater, or diastolic blood pressure of 85 mmHg or greater
5. Fasting glucose level of 100 mg/dL or greater
Metabolic syndrome is thought to be caused by a combination of genetic and lifestyle factors, such as physical inactivity and a diet high in refined carbohydrates and unhealthy fats. Treatment typically involves making lifestyle changes, such as eating a healthy diet, getting regular exercise, and losing weight if necessary. In some cases, medication may also be needed to manage individual components of the syndrome, such as high blood pressure or high cholesterol.
A chromosome is a thread-like structure that contains genetic material, made up of DNA and proteins, in the nucleus of a cell. In humans, there are 23 pairs of chromosomes, for a total of 46 chromosomes, in each cell of the body, with the exception of the sperm and egg cells which contain only 23 chromosomes.
The X chromosome is one of the two sex-determining chromosomes in humans. Females typically have two X chromosomes (XX), while males have one X and one Y chromosome (XY). The X chromosome contains hundreds of genes that are responsible for various functions in the body, including some related to sexual development and reproduction.
Humans inherit one X chromosome from their mother and either an X or a Y chromosome from their father. In females, one of the two X chromosomes is randomly inactivated during embryonic development, resulting in each cell having only one active X chromosome. This process, known as X-inactivation, helps to ensure that females have roughly equal levels of gene expression from the X chromosome, despite having two copies.
Abnormalities in the number or structure of the X chromosome can lead to various genetic disorders, such as Turner syndrome (X0), Klinefelter syndrome (XXY), and fragile X syndrome (an X-linked disorder caused by a mutation in the FMR1 gene).
Intellectual disability (ID) is a term used when there are significant limitations in both intellectual functioning and adaptive behavior, which covers many everyday social and practical skills. This disability originates before the age of 18.
Intellectual functioning, also known as intelligence, refers to general mental capacity, such as learning, reasoning, problem-solving, and other cognitive skills. Adaptive behavior includes skills needed for day-to-day life, such as communication, self-care, social skills, safety judgement, and basic academic skills.
Intellectual disability is characterized by below-average intelligence or mental ability and a lack of skills necessary for day-to-day living. It can be mild, moderate, severe, or profound, depending on the degree of limitation in intellectual functioning and adaptive behavior.
It's important to note that people with intellectual disabilities have unique strengths and limitations, just like everyone else. With appropriate support and education, they can lead fulfilling lives and contribute to their communities in many ways.
DNA Mutational Analysis is a laboratory test used to identify genetic variations or changes (mutations) in the DNA sequence of a gene. This type of analysis can be used to diagnose genetic disorders, predict the risk of developing certain diseases, determine the most effective treatment for cancer, or assess the likelihood of passing on an inherited condition to offspring.
The test involves extracting DNA from a patient's sample (such as blood, saliva, or tissue), amplifying specific regions of interest using polymerase chain reaction (PCR), and then sequencing those regions to determine the precise order of nucleotide bases in the DNA molecule. The resulting sequence is then compared to reference sequences to identify any variations or mutations that may be present.
DNA Mutational Analysis can detect a wide range of genetic changes, including single-nucleotide polymorphisms (SNPs), insertions, deletions, duplications, and rearrangements. The test is often used in conjunction with other diagnostic tests and clinical evaluations to provide a comprehensive assessment of a patient's genetic profile.
It is important to note that not all mutations are pathogenic or associated with disease, and the interpretation of DNA Mutational Analysis results requires careful consideration of the patient's medical history, family history, and other relevant factors.