What If There Were an Autism Saliva Test?

The students in my Latin and ancient Greek classes make it clear, when it comes to taking a test, they'd rather it be on......grammar. Memorizing the endings of the middle/passive voice of verbs or of the third declension (masculine/feminine and neuter) isn't easy, but when it's time for the test, the answers are clear and simple and certain: is, i, em, e, es, um, ibus, es, ibus. When it's time for a translation test, the squirming commences: There are rules for translating from one language into another, but when faced with an actual sentence-- Ἓν οἶδα ὅτι οὐδὲν οἶδα---the rules don't seem to apply, and sometimes need to be broken.

My students crave certainty and even more when so much of the talk is of layoffs and financial crisis, when some of them are not at all certain if they'll be able to finish the semester, much less get their degree, because they've borrowed as much as they can. No less do parents desire certainty about, and even seek control of, their children's health; their children's futures.

This quest for certainty is apparent in the search for a biomarker for autism spectrum disorders. Autism is currently diagnosed in children through observation of a child's behavior, play skills, communication, and there is no biological test that says "this is autism." Were there such biomarkers, diagnosis would be precise and certain, and parents might have a very clear sense of what medical and other treatments to pursue.

All this is why there's been a bit of attention cast on reports of a saliva test for detecting autism being developed by researchers in Italy; a study has been published in the Journal of Proteome Research.

From the January 15th Spectroscopy Now on the study, which is entitled Hypo-Phosphorylation of Salivary Peptidome as a Clue to the Molecular Pathogenesis of Autism Spectrum Disorders:

.....the Italian researchers compared proteins found in the saliva of 27 children with ASD to those in a control group without a diagnosis of ASD. They used reversed-phase high performance liquid chromatography (RP-HPLC) to separate the proteins found in the samples and electrospray ionization mass spectrometry (ESI-MS) to identify the components.

They found that at least one of four protein fragments, the salivary peptides statherin, histatin 1 and acidic proline-rich proteins, in 19 of the children from the ASD group had significantly lower levels of phosphorylation. Phosphorylation is a key biochemical process that activates proteins. "Phosphorylation of salivary peptides involves a Golgi casein kinase [enzyme] common to many organs and tissues, CNS included, whose expression seems to be synchronized during foetal development," the researchers explain.

The team also found that 10 of the children with normal or borderline development also presented "hypo-phosphorylated" salivary peptides. This, the researchers suggest, may indicate that the anomaly could relate mainly to the behavioural aspects of ASD rather than overall mental and physical development.

The Italian results suggest that these abnormal proteins might be indicative of anomalies in the timing of phosphorylation of proteins involved in the development of the central nervous system in early infancy that are thought to be involved in ASD. However, the reduced phosphorylation might also be associated with other pathological conditions rather than ASD.

While the "analysis of salivary phospho-peptides might help to discriminate a considerable subgroup of ASD patients," the summary of the study on Spectroscopy Now reiterates that it's not clear if further clinical testing will reveal if these findings "might relate to ASD if at all." Only 27 participants---a "limited number"---were tested. A January 28th assessment of the "autism saliva test" on ScienceBase includes an interview with lead researcher Massimo Castagnola of the Università Cattolica:

Importantly, hypo-phosphorylation of salivary peptides is not necessarily indicative of ASD, as I mention in my SpecNOW article. Only 18 out of 27 had this characteristic of their salivary peptides. But, hypo-phosphorylation might be present because of another medical problem that may have neurological and/or multifactorial origin.

“Diagnosis of ASD is complex, and ASD is almost certainly a multi-factorial disease,” Castagnola adds, “It would be important to have an early biochemical marker, able to discriminate between different groups of ASD patients.”

There are, however, no practical therapeutic consequences of the Italian research at the moment [my emphasis]. “If future research provides further information, we hope that salivary analysis could be useful in order to address a subgroup of ASD patientssalivary analysis could be useful in order to address a subgroup of ASD patients toward specific therapies,” Castagnola says. “In principle, the non-invasiveness of the test should allow its wide use.”

There is, again, "no therapy that could be applied" after an individual took a potential "autism saliva test"----the function of the test (which, again, is a hypothetical test) would be to show that an individual was on the autism spectrum, and that is all. Certainty of a sort, but the bigger questions of "what to do" remain. And much as we all might wish for certainty, all of this is perhaps a reminder that the effort of trying to figure out what to do, and making mistakes and following leads that don't go anywhere---that this journey may well lead us to an answer, hanging blurrily out there in the distance.

Photo by conskeptical; Ἓν οἶδα ὅτι οὐδὲν οἶδα = "All I know is that I know nothing".