OK, so ultrasounds are more common than in the past, and diagnosis of autism is more common than in the past. Therefore, ultrasounds cause autism. Anyone else see the problem with this reasoning?
But I'll bite, what other evidence does he have? The article is useless, but that doesn't mean anything. Science reporting is almost always poor, without presenting anything useful from the original publications. Unfortunately, I can't get to the full original article by Dr. Casanova (and no other links found on Google Scholar). But here is the abstract:
The phenotypic expression of autism, according to the Triple Hit Hypothesis, is determined by three factors: a developmental time window of vulnerability, genetic susceptibility, and environmental stressors. In utero exposure to thalidomide, valproic acid, and maternal infections are examples of some of the teratogenic agents which increase the risk of developing autism and define a time window of vulnerability. An additional stressor to genetically susceptible individuals during this time window of vulnerability may be prenatal ultrasound. Ultrasound enhances the genesis and differentiation of progenitor cells by activating the nitric oxide (NO) pathway and related neurotrophins. The effects of this pathway activation, however, are determined by the stage of development of the target cells, local concentrations of NO, and the position of nuclei (basal versus apical), causing consequent proliferation at some stages while driving differentiation and migration at others. Ill-timed activation or overactivation of this pathway by ultrasound may extend proliferation, increasing total cell number, and/or may trigger precipitous migration, causing maldistribution of neurons amongst cortical lamina, ganglia, white matter, and germinal zones. The rising rates of autism coincident with the increased use of ultrasound in obstetrics and its teratogenic/toxic effects on the CNS demand further research regarding a putative correlation.I don't know enough about NO pathways and the suggested effects to know how good his reasoning is in this summary. If any biologist/med students reading know about this stuff, I'd love to hear about it in the comments. Also, if anyone has access to the article, I'd be very interested in reading it. (I'm going to try accessing the article when I'm at work tomorrow; I can sometimes get access to articles on Northeastern's wireless service that I don't have at home, but I don't expect this journal to be accessible. If I do, I'll amend this post, or create a new one.)
But even if he is right on about NO pathways, the number of assumptions made from NO activation to autism here suggests to me there's a lot of conjecture that needs to be baked up by evidence. The ending of the summary simply states that rising autism rates coincide with increased use of ultrasound, with no mention of testing all of these connections in the reasoning chain, suggesting he doesn't address them in the paper (or its a poor summary of what research was actually done, which is what I expect to see in an abstract/summary).
Given that, I tentatively suspect that the news article is unnecessarily puffing up a very preliminary idea as something we really need to fear. In addition, it appears that Dr. Casanova may not be very objective:
OK, now I'm much more confident in my assessment. "But this time, he's raising his concerns early?" How can anyone take this seriously? He sees an ultrasound of his grandson, and concludes that must be what did it. You'd think a scientist would be able to separate personal, emotional responses from his research. Or if he can't, at least be aware that his personal experience may be clouding his judgment and be more cautious about drawing conclusions.
This sensationalist article isn't a surprise: it seems to be popular for the news media to encourage people to fear everything about our modern society. I hope this doesn't result in fear of ultrasounds and other important medical procedures, as the anti-vaccine movement has done for vaccinating children.