ScienceDaily (May 26, 2010) — Researchers working with Professor Gudrun Rappold, Director of the Department of Molecular Human Genetics at Heidelberg University Hospital, have discovered previously unknown mutations in autistic and mentally impaired patients in what is known as the SHANK2 gene, a gene that is partially responsible for linking nerve cells.
However, a single gene mutation is not always enough to trigger the illness. In some cases, a certain threshold of mutation must be exceeded. The researchers conclude from their results that a correct inner structure of the nerve cell synapses is necessary to enable the normal development of language, social competence, and cognitive capacity. Essential for the success of the project were the studies by the Heidelberg research team with the doctoral student Simone Berkel and collaboration with a Canadian research team headed by Steve Scherer.
The study has already been published online in the leading scientific journal Nature Genetics.
Autism is a congenital perception and information-processing disorder of the brain that is often associated with low intelligence, but also with above-average intelligence. The disease is characterized by limited social communication and stereotypical or ritualized behavior. Men are affected much more frequently than women. Autism and mental retardation can occur together but also independently of one another and are determined to a great extent by hereditary factors. Some of the responsible genes have already been identified but the precise genetic mechanisms have not yet been explained.
Genetic makeup of hundreds of patients analyzed
Professor Rappold and her team focused their studies on the SHANK2 gene, which encodes a structural protein at the nerve cell synapses. It is responsible for the mesh structure of the basic substance in the postsynapse. Only when the postsynapse is properly structured can nerve impulses be correctly transmitted. The researchers analyzed the genetic material of a total of 396 patients with autism and 184 patients with mental retardation. They found different mutations in their SHANK2 genes in the area of individual base pairs, but also variants in the number of gene copies. The mutations led to varying degrees of symptoms. None of the observed gene variants occurred in healthy control persons. "Apparently an intact postsynaptic structure is especially important for the development of cognitive functions, language, and social competence," explained Professor Rappold.
Identical mutations as the cause of different diseases
Some of the genetic mutations identified were new occurrences of mutations that were not inherited from the parents, but some of the mutations were also found in one parent. Since there are also healthy carriers of gene variants, we must assume that a certain threshold of gene mutations must be exceeded for the disease to appear. "Moreover, the same mutation can be present in an autistic patient with normal intelligence and in a mentally impaired patient," said Professor Rappold. There is some overlap in the clinical symptoms of mental retardation and autism, which can now be explained by a common genetic cause.
A revised sample coordinates the mod wallet.
Thursday, May 27, 2010
Monday, May 24, 2010
Britain bans doctor who linked autism to vaccine
By MARIA CHENG, AP Medical Writer Maria Cheng, Ap Medical Writer – Mon May 24, 9:30 pm ET
LONDON – The doctor whose research linking autism and the vaccine for measles, mumps and rubella influenced millions of parents to refuse the shot for their children was banned Monday from practicing medicine in his native Britain.
Dr. Andrew Wakefield's 1998 study was discredited — but vaccination rates have never fully recovered and he continues to enjoy a vocal following, helped in the U.S. by endorsements from celebrities like Jim Carrey and Jenny McCarthy
Wakefield was the first researcher to publish a peer-reviewed study suggesting a connection between autism and the vaccine for measles, mumps and rubella. Legions of parents abandoned the vaccine, leading to a resurgence of measles in Western countries where it had been mostly stamped out. There are outbreaks across Europe every year and sporadic outbreaks in the U.S.
"That is Andrew Wakefield's legacy," said Paul Offit, chief of infectious diseases at the Children's Hospital of Philadelphia. "The hospitalizations and deaths of children from measles who could have easily avoided the disease."
Wakefield's discredited theories had a tremendous impact in the U.S., Offit said, adding: "He gave heft to the notion that vaccines in general cause autism."
In Britain, Wakefield's research led to a huge decline in the number of children receiving the MMR vaccine: from 95 percent in 1995 — enough to prevent measles outbreaks — to 50 percent in parts of London in the early 2000s. Rates have begun to recover, though not enough to prevent outbreaks. In 2006, a 13-year-old boy became the first person to die from measles in Britain in 14 years.
"The false suggestion of a link between autism and the MMR vaccine has done untold damage to the UK vaccination program," said Terence Stephenson, president of the Royal College of Paediatrics and Child Health. "Overwhelming scientific evidence shows that it is safe."
On Monday, Britain's General Medical Council, which licenses and oversees doctors, found Wakefield guilty of serious professional misconduct and stripped him of the right to practice medicine in the U.K. Wakefield said he plans to appeal the ruling, which takes effect within 28 days.
The council was acting on a finding in January that Wakefield and two other doctors showed a "callous disregard" for the children in their study, published in 1998 in the medical journal Lancet. The medical body said Wakefield took blood samples from children at his son's birthday party, paying them 5 pounds (about $7.20) each and later joked about the incident.
The study has since been widely rejected. From 1998-2004, studies in journals including the Lancet, the New England Journal of Medicine, Pediatrics and BMJ published papers showing no link between autism and the measles vaccine.
Wakefield moved to the U.S. in 2004 and set up an autism research center in Austin, Texas, where he gained a wide following despite being unlicensed as a doctor there and facing skepticism from the medical community. He quit earlier this year.
Offit said he doubted Britain's decision to strip the 53-year-old Wakefield of his medical license would convince many parents that vaccines are safe.
"He's become almost like a Christ-like figure and it doesn't matter that science has proven him wrong," Offit said. "He is a hero for parents who think no one else is listening to them."
Wakefield told The Associated Press Monday's decision was a sad day for British medicine. "None of this alters the fact that vaccines can cause autism," he said.
"These parents are not going away; the children are not going to go away and I most certainly am not going away," he said on NBC's "Today Show."
Wakefield claimed the U.S. government has been settling cases of vaccine-induced autism since 1991.
However, two rulings by a special branch of the U.S. Court of Federal Claims in March and last year found no link between vaccines and autism. More than 5,500 claims have been filed by families seeking compensation for children they claim were hurt by the vaccine.
Wakefield has won support from parents suspicious of vaccines, including Hollywood celebrities.
McCarthy, who has an autistic son, issued a statement in February with then boyfriend Carrey asserting Wakefield was "being vilified through a well-orchestrated smear campaign."
"It is our most sincere belief that Dr. Wakefield and parents of children with autism around the world are being subjected to a remarkable media campaign engineered by vaccine manufacturers," the actors said.
McCarthy, whose best-seller "Louder Than Words" details her search for treatments for her son Evan, wrote the foreword for a new book by Wakefield about autism and vaccines.
In Monday's ruling, the medical council said Wakefield abused his position as a doctor and "brought the medical profession into disrepute."
At the time of his study, Wakefield was working as a gastroenterologist at London's Royal Free Hospital and did not have approval for the research. The study suggested autistic children had a bowel disease and raised the possibility of a link between autism and vaccines. He had also been paid to advise lawyers representing parents who believed their children had been hurt by the MMR vaccine.
Ten of the study's authors later renounced its conclusions and it was retracted by the Lancet in February.
At least a dozen British medical associations, including the Royal College of Physicians, the Medical Research Council and the Wellcome Trust have issued statements verifying the safety of the measles, mumps and rubella vaccine.
This verdict is not about (the measles) vaccine," said Adam Finn, a professor of pediatrics at the University of Bristol Medical School. "We all now know that the vaccine is remarkably safe and enormously effective... We badly need to put this right for the sake of our own children and children worldwide."
LONDON – The doctor whose research linking autism and the vaccine for measles, mumps and rubella influenced millions of parents to refuse the shot for their children was banned Monday from practicing medicine in his native Britain.
Dr. Andrew Wakefield's 1998 study was discredited — but vaccination rates have never fully recovered and he continues to enjoy a vocal following, helped in the U.S. by endorsements from celebrities like Jim Carrey and Jenny McCarthy
Wakefield was the first researcher to publish a peer-reviewed study suggesting a connection between autism and the vaccine for measles, mumps and rubella. Legions of parents abandoned the vaccine, leading to a resurgence of measles in Western countries where it had been mostly stamped out. There are outbreaks across Europe every year and sporadic outbreaks in the U.S.
"That is Andrew Wakefield's legacy," said Paul Offit, chief of infectious diseases at the Children's Hospital of Philadelphia. "The hospitalizations and deaths of children from measles who could have easily avoided the disease."
Wakefield's discredited theories had a tremendous impact in the U.S., Offit said, adding: "He gave heft to the notion that vaccines in general cause autism."
In Britain, Wakefield's research led to a huge decline in the number of children receiving the MMR vaccine: from 95 percent in 1995 — enough to prevent measles outbreaks — to 50 percent in parts of London in the early 2000s. Rates have begun to recover, though not enough to prevent outbreaks. In 2006, a 13-year-old boy became the first person to die from measles in Britain in 14 years.
"The false suggestion of a link between autism and the MMR vaccine has done untold damage to the UK vaccination program," said Terence Stephenson, president of the Royal College of Paediatrics and Child Health. "Overwhelming scientific evidence shows that it is safe."
On Monday, Britain's General Medical Council, which licenses and oversees doctors, found Wakefield guilty of serious professional misconduct and stripped him of the right to practice medicine in the U.K. Wakefield said he plans to appeal the ruling, which takes effect within 28 days.
The council was acting on a finding in January that Wakefield and two other doctors showed a "callous disregard" for the children in their study, published in 1998 in the medical journal Lancet. The medical body said Wakefield took blood samples from children at his son's birthday party, paying them 5 pounds (about $7.20) each and later joked about the incident.
The study has since been widely rejected. From 1998-2004, studies in journals including the Lancet, the New England Journal of Medicine, Pediatrics and BMJ published papers showing no link between autism and the measles vaccine.
Wakefield moved to the U.S. in 2004 and set up an autism research center in Austin, Texas, where he gained a wide following despite being unlicensed as a doctor there and facing skepticism from the medical community. He quit earlier this year.
Offit said he doubted Britain's decision to strip the 53-year-old Wakefield of his medical license would convince many parents that vaccines are safe.
"He's become almost like a Christ-like figure and it doesn't matter that science has proven him wrong," Offit said. "He is a hero for parents who think no one else is listening to them."
Wakefield told The Associated Press Monday's decision was a sad day for British medicine. "None of this alters the fact that vaccines can cause autism," he said.
"These parents are not going away; the children are not going to go away and I most certainly am not going away," he said on NBC's "Today Show."
Wakefield claimed the U.S. government has been settling cases of vaccine-induced autism since 1991.
However, two rulings by a special branch of the U.S. Court of Federal Claims in March and last year found no link between vaccines and autism. More than 5,500 claims have been filed by families seeking compensation for children they claim were hurt by the vaccine.
Wakefield has won support from parents suspicious of vaccines, including Hollywood celebrities.
McCarthy, who has an autistic son, issued a statement in February with then boyfriend Carrey asserting Wakefield was "being vilified through a well-orchestrated smear campaign."
"It is our most sincere belief that Dr. Wakefield and parents of children with autism around the world are being subjected to a remarkable media campaign engineered by vaccine manufacturers," the actors said.
McCarthy, whose best-seller "Louder Than Words" details her search for treatments for her son Evan, wrote the foreword for a new book by Wakefield about autism and vaccines.
In Monday's ruling, the medical council said Wakefield abused his position as a doctor and "brought the medical profession into disrepute."
At the time of his study, Wakefield was working as a gastroenterologist at London's Royal Free Hospital and did not have approval for the research. The study suggested autistic children had a bowel disease and raised the possibility of a link between autism and vaccines. He had also been paid to advise lawyers representing parents who believed their children had been hurt by the MMR vaccine.
Ten of the study's authors later renounced its conclusions and it was retracted by the Lancet in February.
At least a dozen British medical associations, including the Royal College of Physicians, the Medical Research Council and the Wellcome Trust have issued statements verifying the safety of the measles, mumps and rubella vaccine.
This verdict is not about (the measles) vaccine," said Adam Finn, a professor of pediatrics at the University of Bristol Medical School. "We all now know that the vaccine is remarkably safe and enormously effective... We badly need to put this right for the sake of our own children and children worldwide."
Thursday, May 13, 2010
Brain clue may explain condition's 'hug avoidance'
Delays at crucial points during the development of the brain in the womb may explain why people with a condition linked to autism do not like hugs.
A study in mice with fragile X syndrome found wiring in the part of the brain that responds to touch is formed late.
The findings may help explain why people with the condition are hypersensitive to physical contact, the researchers wrote in Neuron.
It also points to key stages when treatment could be most effective.
Fragile X syndrome is caused by a mutant gene in the X chromosome that interferes in the production of a protein called fragile X mental retardation protein (FMRP).
Under normal circumstances, the protein directs the formation of other proteins that build synapses in the brain.
Boys are usually more severely affected with the condition - which is the leading known cause of autism - because they have only one X chromosome.
In addition to mental impairment, hyperactivity, emotional and behavioural problems, anxiety and mood swings, people with fragile X also show what doctors call "tactile defensiveness", which means they do not make eye contact and do not like physical contact and are hypersensitive to touch and sound.
Connections
By recording electrical signals in the brains of mice, bred to mimic the condition, the researchers found that connections in the sensory cortex in the brain were late to mature.
This "mistiming" may trigger a domino effect and cause further problems with the correct wiring of the brain, they concluded.
The study also found these changes in the brain's connections occur much earlier than previously thought, midway through a baby's development in the womb.
And it suggests there are key "windows" when treatments for fragile X and autism could be most effective, they said.
Professor Peter Kind, who led the study at the University of Edinburgh, added: "We've learned these changes happen much earlier than previously thought, which gives valuable insight into when we should begin therapeutic intervention for people with these conditions.
"It also has implications for the treatment of autism since the changes in the brains of fragile X and autistic people are thought to significantly overlap."
Dr Gina Gómez de la Cuesta, from the National Autistic Society, said research into fragile X syndrome could help understanding of certain aspects of autism.
"Autism is common in people with fragile X syndrome, however there are many other causes of autism, most of which are not yet fully understood.
"Understanding how the brain works when a person has fragile X syndrome could help put some of the pieces together about what is happening in the brain when a person has autism, but it is not the whole story.
"Animal research can tell us a lot about genetics and the brain, but it is only a small part of the picture and further research would be required before we fully understand any links to autism."
A study in mice with fragile X syndrome found wiring in the part of the brain that responds to touch is formed late.
The findings may help explain why people with the condition are hypersensitive to physical contact, the researchers wrote in Neuron.
It also points to key stages when treatment could be most effective.
Fragile X syndrome is caused by a mutant gene in the X chromosome that interferes in the production of a protein called fragile X mental retardation protein (FMRP).
Under normal circumstances, the protein directs the formation of other proteins that build synapses in the brain.
Boys are usually more severely affected with the condition - which is the leading known cause of autism - because they have only one X chromosome.
In addition to mental impairment, hyperactivity, emotional and behavioural problems, anxiety and mood swings, people with fragile X also show what doctors call "tactile defensiveness", which means they do not make eye contact and do not like physical contact and are hypersensitive to touch and sound.
Connections
By recording electrical signals in the brains of mice, bred to mimic the condition, the researchers found that connections in the sensory cortex in the brain were late to mature.
This "mistiming" may trigger a domino effect and cause further problems with the correct wiring of the brain, they concluded.
The study also found these changes in the brain's connections occur much earlier than previously thought, midway through a baby's development in the womb.
And it suggests there are key "windows" when treatments for fragile X and autism could be most effective, they said.
Professor Peter Kind, who led the study at the University of Edinburgh, added: "We've learned these changes happen much earlier than previously thought, which gives valuable insight into when we should begin therapeutic intervention for people with these conditions.
"It also has implications for the treatment of autism since the changes in the brains of fragile X and autistic people are thought to significantly overlap."
Dr Gina Gómez de la Cuesta, from the National Autistic Society, said research into fragile X syndrome could help understanding of certain aspects of autism.
"Autism is common in people with fragile X syndrome, however there are many other causes of autism, most of which are not yet fully understood.
"Understanding how the brain works when a person has fragile X syndrome could help put some of the pieces together about what is happening in the brain when a person has autism, but it is not the whole story.
"Animal research can tell us a lot about genetics and the brain, but it is only a small part of the picture and further research would be required before we fully understand any links to autism."
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