The quotes from this study and Prometheus show that it is far from a certain thing.

and this:

“Our data show that putative disease associations, such as the reported high frequency of m.3243AG in diabetes mellitus could be a chance finding irrelevant to pathogenesis.”

Let’s go back and review some quotes from “experts” oft quoted here talking about mtDNA mutations.

Dr. Novella:
“This makes option 4 very plausible – it would be an incredible coincidence if this child just happened to have a mutation in a gene that was known to cause their exact constellation of neurological signs and symptoms and yet the mutation was not the sole or primary cause of those symptoms.”

Orac:
“Ultimately, a metabolic disorder, specifically a mitochondrial disorder was suspected, and ultimately confirmed through genetic testing, which showed “a mitochondrial DNA (“mtDNA”) point mutation analysis revealed a single nucleotide change in the 16S ribosomal RNA gene (T2387C).” As part of her course, the child also developed a seizure disorder.”

Dr. DiMauri:
“Salvatore DiMauro, who has studied links between autism and mitochondrial mutations at Columbia University in New York, agrees. “My guess is that if she had a mitochondrial mutation, sooner or later she would have shown something abnormal,” he says.”

This statement is quite correct.
“Perhaps Mr. Kirby should read the entire article before screaming, “The sky is falling!””

And I think this applies to a lot of other people too.

The mtDNA codes for 37 genes, 22 tRNA’s, 2 rRNA’s and 13 proteins. That’s all. The rest of the genes needed for the mitochondria to function and reproduce are on the chromosomes – they’ve moved there over evolutionary time.

Because each mitochondrion has between 5 and 12 copies of its DNA and each human cell has somewhere between a few dozen to hundreds of mitochondria, there are a lot of mtDNA copies. And since there are a lot of mitochondria, it is possible to have a mutation – even a serious mutation – in some of them and still have the cell keep running along normally.

Finally, all of the mitochondria in mammalian (including human) cells come from the mother, so there is no transmission of mtDNA mutations from father to children.

What was interesting about the study is that they found so many mutations in the mtDNA – more than would have been predicted from the number of people with clinically apparent mitochondrial diseases.

And what makes this even more interesting is that a lot of mitochondrial diseases are caused by mutations of genes located on the chromosomes, so mtDNA mutations would be expected to cause only a fraction of mitochondrial diseases.

Of the 15 subjects with mtDNA mutations, 3 had a mutation in the NADH subunit 6 gene (T14484C) – which is associated with Leber Hereditary Optic Neuropathy (LHON). Two had 100% of their mtDNA with this mutation and the other had 89%. Another child had a G11778A mutation in 100% of the mtDNA – this mutation is also associated with LHON.

The other 11 children with detected mtDNA mutations all had less than 75% of their mtDNA involved; most had less than 10% (median = 10.2%).

The authors were able to go back and get blood samples from eight of the mothers of the children with mtDNA mutations. Of the three children with 100% of their mtDNA showing mutations, the two mothers (one set of twins) also had 100% of their mtDNA with the same mutation.

Since the disease associated with these mtDNA mutations (LHON) is manifested in early adult life, it is curious that none of the mothers was reported to have a mitochondrial disorder, especially since one of the authors – Patrick Chinnery – is an expert on LHON. Of course, LHON is only clinically apparent in 50% of the males and 15% of the females with the mutation. Still, with 100% of their mtDNA showing the mutation, it is curious that none of them manifested the disease.

I have to agree with the authors in their conclusion:

“Detecting heteroplasmic mtDNA mutations in [greater than] 1 in 200 individuals of the background population has implications for studies reporting mtDNA mutations in specific disease groups. Our data show that putative disease associations, such as the reported high frequency of m.3243A/G in diabetes mellitus could be a chance finding irrelevant to pathogenesis.”

Perhaps Mr. Kirby should read the entire article before screaming, “The sky is falling!”

Prometheus

It sound like it is children of female carriers which means male or female.

I am not suggesting David intended to mislead people with the 1 in 200 figure I merely want to highlight the fact that it is not as cut and dried as that.

I am. I think Kirby knows damned well that, even if the study is correct, it does not mean that 1/200 people have mitochondrial disease (has Kirby ever heard of “silent” mutations?) or that their offspring are somehow susceptible to “vaccine-induced autism.” He’s just being David Kirby and laying down an intense screen of B.S. to obfuscate the fact that his claim that vaccines somehow cause or “trigger” autism is the incredible shrinking hypothesis.

Indeed, your estimate of 1/160,000 that two parents would produce a homozygous mutation is really too high, mainly because that’s for just one gene assuming that the rate of that one mutation is 1/200. The odds are really much lower than 1/160,000.