Congenital cytomegalovirus (CMV) infection and autism continued

I wanted to briefly talk about the paper by Francesca Garofoli and colleagues [1] on congenital cytomegalovirus (CMV) infection and autism not because it contains any novel data (see here), but because it reminds us that the potential 'pathways' to a diagnosis of autism are multiple and not necessarily 'pre-programmed' as per the 'it's all genetic' arguments that frequently figure in various domains.

Congenital CMV infection refers to the transmission of CMV - "a common virus that belongs to the herpes family of viruses" - from mother to foetus during pregnancy. The details are still under investigation as to how and why CMV affects a foetus (bearing in mind this is quite a common virus) but autism as a consequence of [some] congenital CMV infection has growing evidence-based support [2].

Garofoli et al included 70 'proven' cases of CMV "congenitally-infected infants" in their study; specifically looking "to correlate congenital cytomegalovirus (CMV) infection with autism spectrum disorder (ASD) and to define its prevalence." They determined that 2 of their 70 strong cohort met criteria for an ASD at the age of 3 years. Two of 70 translated as 2.8% of their cohort and contrasts with [estimated] autism prevalence "in general Italian population (0.66-1.36%)." The figure of 2.8% is also not a million miles away from other estimates of autism suggested via congenital CMV infection [3].

Although 2.8% of the cohort (2/70) might not sound like a lot I'm inclined to suggest that it does prompt quite a lot more additional investigation. Not least is the question: 'why was autism/ASD not diagnosed in the other 68 children?' and onward whether other factors (genetics(!), biology, infection timing, immunologic response, etc) might come into play [4] in relation to the congenital CMV infection - autism association? Taking also into account the estimated prevalence of ASD in Italy, these figures (estimates) do seem to be a little lower than that described in other geographical locations (see here and see here for examples). Indeed, bearing in mind the research evidence already looking at estimated ASD prevalence in Italy [5] it's not unfair to say that 'under-estimation' might be a familiar theme...

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[1] Garofoli F. et al. An Italian Prospective Experience on the Association Between Congenital Cytomegalovirus Infection and Autistic Spectrum Disorder. J Autism Dev Disord. 2017 Mar 3.

[2] Ornoy A. et al. Prenatal factors associated with autism spectrum disorder (ASD). Reprod Toxicol. 2015 Aug 15;56:155-69.

[3] Engman ML. et al. Prenatal acquired cytomegalovirus infection should be considered in children with autism. Acta Paediatr. 2015 Aug;104(8):792-5.

[4] Lombardo MV. et al. Maternal immune activation dysregulation of the fetal brain transcriptome and relevance to the pathophysiology of autism spectrum disorder. Mol. Psychiatr. 2017. March 21.

[5] Ferrante M. et al. Prevalence and age at diagnosis of Autism Spectrum Disorder in south Italy, 2004–2014. Eur J Public Health. 2015; 25 (suppl_3).

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Garofoli F, Lombardi G, Orcesi S, Pisoni C, Mazzucchelli I, Angelini M, Balottin U, & Stronati M (2017). An Italian Prospective Experience on the Association Between Congenital Cytomegalovirus Infection and Autistic Spectrum Disorder. Journal of autism and developmental disorders PMID: 28258350