I had planned to write a new post on the genetic origins of OCD today.
But whilst scanning new research, I learned that this effort will take a bit of time. The situation anno 2017 is markedly different from that in, say, 2007.
For instance, there’s the vast field of epigenetics, it has been expanding at a rapid pace. I quote this brief explanation from Wikipedia:
Epigenetics are stable heritable traits (or “phenotypes“) that cannot be explained by changes in DNA sequence. The Greek prefix epi- (Greek: επί– over, outside of, around) in epigenetics implies features that are “on top of” or “in addition to” the traditional genetic basis for inheritance. Epigenetics often refers to changes in a chromosome that affect gene activity and expression, but can also be used to describe any heritable phenotypic change that does not derive from a modification of the genome, such as prions. Such effects on cellular and physiological phenotypic traits may result from external or environmental factors, or be part of normal developmental program. The standard definition of epigenetics requires these alterations to be heritable, either in the progeny of cells or of organisms.
Epigenetics is the key link between our DNA proper and our environment. The old expression to describe the interaction between genes and surroundings is: G x E.
I am almost inclined to say: the mysterious x-factor in this small formula is epigenetics.
The acronym PANDAS stands for:
pediatric autoimmune neuropsychiatric disorders associated with Streptococcus infections.
That is a whole mouthful, you’ll agree.
We’re talking about a unique sub-set of psychiatric patients: there are children in whom an acute manifestation of OCD and/or tic disorders occurs. This is special, because with OCD the symptoms usually develop over time.
The disorders were initially thought to be caused by infection with Group-A beta-hemolytic Streptococcus (GABHS).
Susan Swedo and her group published an important research report on this in 1998.
Two decades later, there have been changes in the concept of PANDAS; actually, it is now named: PANS (pediatric acute-onset neuropsychiatric syndrome). It hasn’t been accepted as a distinct disorder (or group of disorders) yet – but that doesn’t mean there haven’t been additional findings.
- several agents other than Streptococcus may be involved in its inception
- there is a male predominance in the patient population: 65% of it is male
- 54% of those affected show a specific association with Streptococcus
- gender and pubertal status have a strong effect on symptom course and chronicity of the illness
- the rate of co-occurring medical illness is high – a general immune dysfunction is suggested by experts
- PANS has a considerable impact on the daily life of the children
- antibiotic treatment is advised to resolve the symptoms of infection early on
- it may be that the resident immune cells of the brain, the microglia, aren’t functioning well in PANS
Now, we are lucky: some fine articles on these matters are available at the open source of the National Institute for Mental Health, in Bethesda, Maryland, via the Pubmed site:
…and here’s a figure (sans comment) to whet your appetite, from the first article: