No link between vaccines and autism (again)

by Liza on Jul. 06th, 2006

A study published in the most recent issue of Pediatrics shows that the rate of autism and related disorders increased even as thimerosal (a mercury preservative) was eliminated from vaccines and fewer children received the MMR vaccine. The study looked at 28,000 children over 11 years. This and other studies confirm that there is no evidence to suggest that the MMR vaccine increases the risk of autism.

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Liza's picture
Liza says:

A small study published in June 2006 in Biological Psychiatry suggests that autism spectrum disorders may result from abnormal early fetal development.

Scientists looked at preserved placentas from children later diagnosed with autism, and compared them to placentas of children with normal development. The placentas from autistic children were 3 times more likely to contain "trophoblastic inclusions." (Trophoblasts are among the first cells to form during fetal development, and are essential for implantation and placental development.) Trophoblast inclusions have been associated with a number of other genetic abnormalities, and the presence of trophoblasts in fully-formed placentas may not affect their function, but could be markers for genetic predispositions "that could have subtle, yet profound, effects in the developing embryo an the forming nervous system."

posted on Thu, 10/19/2006 - 10:31am
Liza's picture
Liza says:

A study published in the Archives of General Psychiatry found that men in their 40s are almost six times more likely to father children with autism spectrum disorders than men in their 20s. (There was no relationship between mother's ages and autism.)

"Maternal and paternal ages have been associated with other neurodevelopmental disorders and have been considered in some previous studies of autism spectrum disorders. Advancing maternal age increases the risk of chromosomal abnormalities, such as Down's syndrome, and has been associated with the risk of brain damage during pregnancy, dyslexia, and mental retardation of unknown cause."

Older men are more likely to father children with certain congenital disorders, including Apert's syndrome.

The authors of the study continued:

"Among the possible mechanisms for an effect of paternal age on autism spectrum disorders risk are point mutations or structural chromosomal aberrations in the father's germline, or imprinting, in which an allele inherited from the father suppresses the expression of the mother's allele and determines the expression of a particular gene.

Although our understanding of genetic imprinting is nascent, it merits consideration in autism. Imprinted genes play a key role in brain development, investigations of Turner's syndrome suggest a role for imprinted genes in language development and social functioning, and parent-of-origin effects have been reported in Angelman's syndrome and in at least some autism studies."

posted on Thu, 10/19/2006 - 11:45am

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