The serum profiles observed in the case of fetal trisomy 21 are characterized at the end of the first trimester by decreased PAPP-A and increased free hCGβ levels; in the second trimester, it is characterized by a decrease in the AFP and uE3 levels and an increase in the hCG, free hCGβ and inhA levels [15,172] (Figure .
What biological process results in Down syndrome?
Down syndrome is usually caused by an error in cell division called “nondisjunction.” Nondisjunction results in an embryo with three copies of chromosome 21 instead of the usual two. Prior to or at conception, a pair of 21st chromosomes in either the sperm or the egg fails to separate..
What is the biochemistry behind Down syndrome?
In 95% of cases, Down syndrome is caused by nondisjunction during cell division, resulting in an extra chromosome 21 (trisomy 21). Most cases of Down syndrome involve a nondisjunction during the first meiotic cell division, with mothers contributing the extra chromosome in 85% of cases..
What is the biochemistry of Down syndrome?
In 95% of cases, Down syndrome is caused by nondisjunction during cell division, resulting in an extra chromosome 21 (trisomy 21). Most cases of Down syndrome involve a nondisjunction during the first meiotic cell division, with mothers contributing the extra chromosome in 85% of cases..
Which biochemical test is high in Down syndrome?
Maternal serum screening for Down syndrome is an established practise in many countries. In the second trimester human chorionic gonadotrophin (hCG) or free beta-hCG is the marker of first choice, with alpha-fetoprotein (AFP) as the second marker and unconjugated oestriol (uE(3)) the third..
Which genetics is involved in Down syndrome?
Down syndrome (DS) is caused by trisomy of human chromosome 21 (Hsa21) and results in a large number of phenotypes, including learning difficulties, cardiac defects, distinguishing facial features and leukaemia..
Inheritance. Most cases of Down syndrome are not inherited. When the condition is caused by trisomy 21, the chromosomal abnormality occurs as a random event during the formation of reproductive cells in a parent. The abnormality usually occurs in egg cells, but it occasionally occurs in sperm cells.
Researchers believe that having extra copies of genes on chromosome 21 disrupts the course of normal development, causing the characteristic features of Down syndrome and the increased risk of health problems associated with this condition.
The serum profiles observed in the case of fetal trisomy 21 are characterized at the end of the first trimester by decreased PAPP-A and increased free hCGβ levels; in the second trimester, it is characterized by a decrease in the AFP and uE3 levels and an increase in the hCG, free hCGβ and inhA levels [15,172] (Figure
Abstract. Maternal serum screening for Down syndrome is an established practise in many countries. In the second trimester human chorionic gonadotrophin (hCG)
Maternal serum screening for Down syndrome is an established practise in many countries. In the second trimester human chorionic gonadotrophin (hCG) or free
Can genetic and epigenetic studies help treat Down syndrome?
These genetic and epigenetic studies are starting to uncover fundamental biological mechanisms, leading to insights that may soon become therapeutically relevant. Here we review recent progress in genetic and epigenetic analysis of Down syndrome (DS), caused by trisomy of chromosome 21.
Does the down Medical Center provide medical care for people with Down syndrome?
The Down Medical Center provides medical care specifically for individuals with DS and possesses over 2,500 medical records (more than 50% of the estimated Down syndrome population in Catalonia); therefore, it reflects the population with DS in our geographic area.
Is chromosome 21 a phenotype of Down syndrome?
Mol Cell Biol 20:
648–655 [ PMC free article] [ PubMed] [ Google Scholar] The presence of an extra copy of human chromosome 21 (Hsa21) leads to a constellation of phenotypic manifestations in Down syndrome (DS)
including :
prominent effects on the brain and immune system. Intensive efforts to unravel the molecular mechanisms ..
Is Down syndrome a chromosomal disorder?
Down syndrome (DS) is the most common worldwide cause of intellectual disability of genetic origin and the most common chromosomal disorder affecting live-born infants. In addition to intellectual disability, individuals with DS have other comorbidities and complex medical conditions.
Biochemistry down syndrome
Symptoms that can occur following a reduction in alcohol use after a period of excessive use
Alcohol withdrawal syndrome (AWS) is a set of symptoms that can occur following a reduction in alcohol use after a period of excessive use. Symptoms typically include anxiety, shakiness, sweating, vomiting, fast heart rate, and a mild fever. More severe symptoms may include seizures, and delirium tremens (DTs) which can be fatal in untreated patients. Symptoms start at around 6 hours after last drink. Peak incidence of seizures occurs at 24-36 hours and peak incidence of delirium tremens is at 48-72 hours.
Benzodiazepine withdrawal syndrome
Signs and symptoms due to benzodiazepines discontinuation in physically dependent persons
Benzodiazepine withdrawal syndrome is the cluster of signs and symptoms that may emerge when a person who has been taking benzodiazepines as prescribed develops a physical dependence on them and then reduces the dose or stops taking them without a safe taper schedule.
Chronic fatigue syndrome (CFS)
Medical condition
Chronic fatigue syndrome (CFS), also called myalgic encephalomyelitis (ME) or ME/CFS, is a complex, debilitating, long-term medical condition. Core symptoms are lengthy flare-ups of the illness following ordinary minor physical or mental activity, known as post-exertional malaise (PEM); greatly diminished capacity to do tasks that were routine before the illness; and sleep disturbances. The Center for Disease Control and Prevention's (CDC) diagnostic criteria also require at least one of the following: (1) orthostatic intolerance or (2) impaired memory or attention. Frequently and variably, other symptoms occur involving numerous body systems, and chronic pain is very common. The often incapacitating fatigue in ME/CFS is different from that caused by normal strenuous exertion, is not significantly relieved by rest, and is not due to a previous medical condition. Diagnosis is based on the person's symptoms because no confirmed diagnostic test is available.
Hunter syndrome
Medical condition
Hunter syndrome, or mucopolysaccharidosis type II, is a rare genetic disorder in which large sugar molecules called glycosaminoglycans build up in body tissues. It is a form of lysosomal storage disease. Hunter syndrome is caused by a deficiency of the lysosomal enzyme iduronate-2-sulfatase (I2S). The lack of this enzyme causes heparan sulfate and dermatan sulfate to accumulate in all body tissues. Hunter syndrome is the only MPS syndrome to exhibit X-linked recessive inheritance.
Medical condition
Kallmann syndrome (KS) is a genetic disorder that prevents a person from starting or fully completing puberty. Kallmann syndrome is a form of a group of conditions termed hypogonadotropic hypogonadism. To distinguish it from other forms of hypogonadotropic hypogonadism, Kallmann syndrome has the additional symptom of a total lack of sense of smell (anosmia) or a reduced sense of smell. If left untreated, people will have poorly defined secondary sexual characteristics, show signs of hypogonadism, almost invariably are infertile and are at increased risk of developing osteoporosis. A range of other physical symptoms affecting the face, hands and skeletal system can also occur.
Range of genetic disorders which cause a person to appear to grow older faster
Progeroid syndromes (PS) are a group of rare genetic disorders that mimic physiological aging, making affected individuals appear to be older than they are. The term progeroid syndrome does not necessarily imply progeria, which is a specific type of progeroid syndrome.
Shaken baby syndrome (SBS)
Medical condition
Shaken baby syndrome (SBS), also known as abusive head trauma (AHT), is a medical condition in children younger than five years old, generally caused by blunt trauma, vigorous shaking, or a combination of both. SBS is the leading cause of fatal head injuries in children under two, with a risk of death of about 25%. The most common symptoms include retinal bleeds, multiple fractures of the long bones, and subdural hematomas.
Smith–Lemli–Opitz syndrome is an inborn error of cholesterol synthesis
Medical condition
Smith–Lemli–Opitz syndrome is an inborn error of cholesterol synthesis. It is an autosomal recessive, multiple malformation syndrome caused by a mutation in the enzyme 7-Dehydrocholesterol reductase encoded by the DHCR7 gene. It causes a broad spectrum of effects, ranging from mild intellectual disability and behavioural problems to lethal malformations.
Werner syndrome (WS) or Werner's syndrome
Medical condition
Werner syndrome (WS) or Werner's syndrome, also known as adult progeria, is a rare, autosomal recessive disorder which is characterized by the appearance of premature aging.
Medical condition
ZTTK syndrome is a rare disease caused in humans by a genetic mutation of the SON gene. Common symptoms include developmental delay and sometimes moderate to several intellectual disability.
Alcohol withdrawal syndrome (AWS) is a set of symptoms that can occur
Symptoms that can occur following a reduction in alcohol use after a period of excessive use
Alcohol withdrawal syndrome (AWS) is a set of symptoms that can occur following a reduction in alcohol use after a period of excessive use. Symptoms typically include anxiety, shakiness, sweating, vomiting, fast heart rate, and a mild fever. More severe symptoms may include seizures, and delirium tremens (DTs) which can be fatal in untreated patients. Symptoms start at around 6 hours after last drink. Peak incidence of seizures occurs at 24-36 hours and peak incidence of delirium tremens is at 48-72 hours.
Benzodiazepine withdrawal syndrome
Signs and symptoms due to benzodiazepines discontinuation in physically dependent persons
Benzodiazepine withdrawal syndrome is the cluster of signs and symptoms that may emerge when a person who has been taking benzodiazepines as prescribed develops a physical dependence on them and then reduces the dose or stops taking them without a safe taper schedule.
Chronic fatigue syndrome (CFS)
Medical condition
Chronic fatigue syndrome (CFS), also called myalgic encephalomyelitis (ME) or ME/CFS, is a complex, debilitating, long-term medical condition. Core symptoms are lengthy flare-ups of the illness following ordinary minor physical or mental activity, known as post-exertional malaise (PEM); greatly diminished capacity to do tasks that were routine before the illness; and sleep disturbances. The Center for Disease Control and Prevention's (CDC) diagnostic criteria also require at least one of the following: (1) orthostatic intolerance or (2) impaired memory or attention. Frequently and variably, other symptoms occur involving numerous body systems, and chronic pain is very common. The often incapacitating fatigue in ME/CFS is different from that caused by normal strenuous exertion, is not significantly relieved by rest, and is not due to a previous medical condition. Diagnosis is based on the person's symptoms because no confirmed diagnostic test is available.
Hunter syndrome
Medical condition
Hunter syndrome, or mucopolysaccharidosis type II, is a rare genetic disorder in which large sugar molecules called glycosaminoglycans build up in body tissues. It is a form of lysosomal storage disease. Hunter syndrome is caused by a deficiency of the lysosomal enzyme iduronate-2-sulfatase (I2S). The lack of this enzyme causes heparan sulfate and dermatan sulfate to accumulate in all body tissues. Hunter syndrome is the only MPS syndrome to exhibit X-linked recessive inheritance.
Medical condition
Kallmann syndrome (KS) is a genetic disorder that prevents a person from starting or fully completing puberty. Kallmann syndrome is a form of a group of conditions termed hypogonadotropic hypogonadism. To distinguish it from other forms of hypogonadotropic hypogonadism, Kallmann syndrome has the additional symptom of a total lack of sense of smell (anosmia) or a reduced sense of smell. If left untreated, people will have poorly defined secondary sexual characteristics, show signs of hypogonadism, almost invariably are infertile and are at increased risk of developing osteoporosis. A range of other physical symptoms affecting the face, hands and skeletal system can also occur.
Range of genetic disorders which cause a person to appear to grow older faster
Progeroid syndromes (PS) are a group of rare genetic disorders that mimic physiological aging, making affected individuals appear to be older than they are. The term progeroid syndrome does not necessarily imply progeria, which is a specific type of progeroid syndrome.
Shaken baby syndrome (SBS)
Medical condition
Shaken baby syndrome (SBS), also known as abusive head trauma (AHT), is a medical condition in children younger than five years old, generally caused by blunt trauma, vigorous shaking, or a combination of both. SBS is the leading cause of fatal head injuries in children under two, with a risk of death of about 25%. The most common symptoms include retinal bleeds, multiple fractures of the long bones, and subdural hematomas.
Smith–Lemli–Opitz syndrome is an inborn error of cholesterol synthesis
Medical condition
Smith–Lemli–Opitz syndrome is an inborn error of cholesterol synthesis. It is an autosomal recessive, multiple malformation syndrome caused by a mutation in the enzyme 7-Dehydrocholesterol reductase encoded by the DHCR7 gene. It causes a broad spectrum of effects, ranging from mild intellectual disability and behavioural problems to lethal malformations.
Werner syndrome (WS) or Werner's syndrome
Medical condition
Werner syndrome (WS) or Werner's syndrome, also known as adult progeria, is a rare, autosomal recessive disorder which is characterized by the appearance of premature aging.
Medical condition
ZTTK syndrome is a rare disease caused in humans by a genetic mutation of the SON gene. Common symptoms include developmental delay and sometimes moderate to several intellectual disability.
