A family I know has pyloric stenosis (PS) right through the generations, three that I know of. PS is a badge of their tribe, and that could be quite affirming, even fun. I can feel quite envious of them: even if they hate their scar and have PTSD (trauma) from their surgery, they learnt very early that they were not freaks but really belong to their talented and energetic clan! Other PS families tell stories like that on the web, often light-heartedly.
It took me most of my 66 years to get anywhere near that feeling of being OK and belonging. My parents could never bring themselves to explain my scar and left me feeling exposed, speechless and unusual at an age when that was traumatic in a variety of situations: as a child in the bath, in the school gym, at the beach, on hot days. It was nearly 30 years before I met others with a similar scar and realised I was not a unique freak and in fact belong to the enormous PS Club.
It’s only recently that I’ve taken to heart that feeling painfully unique in my family is something that happens to lots of people. Today some medical reports are being published free and online like the one which enabled me to discover why certain defects of infancy occur just once in some families and many times over in others.
For a reader with a PS history who is able to pick up the basics from among a lot of scientific terminology, the article referred to is fascinating to browse-read: it will give you a glimpse of the gene technology that can now increasingly unlock new information about how we are constructed. I’ll attempt to glean the main facts here…
The term “multifactorial” is often used when conditions of infancy like cerebral palsy, cleft lip and cleft palate, heart defects, PS and other abdominal conditions, and spinal and neural tube defects like spinal bifida. “Multifactorial” means they are caused by any of a mix of genetic and environmental causes.
The report cited shows clearly that any of several genes may be involved when a baby has PS or other multifactorial conditions. The report details a study of PS in an extended family where it was tracked to chromosome 16q24; but the study also found that the genes of 14 other PS-affected families did not link their PS with this chromosome. It also found that the PS-linked chromosome in multiple PS families seems stronger (about 2 boys to every girl baby) than in isolated cases of PS (4-5 boys to every girl). So PS may arise from any one (or more) of several chromosomes – which are still being explored.
Again taking PS as an example, put together the fact that just two or three different gene loci (positions on our chromosomes) have been identified so far that can be linked with PS, and add to that any number of “environmental” factors, just some of which were mentioned in my previous post, like the richness and abundance of the milk the baby gets. Additional “environmental” factors identified as possible triggers of PS include bio-chemical conditions in the baby’s gut too complex to explain further here, the mother’s age and stress level, whether the baby is breast or bottle fed, the family’s socio-economic circumstances, and other birth defects, as PS comes together with other gut, chest and heart defects and conditions like Asperger’s disease far more often than average.
I’ve often wondered why I seemed to be the only one in my family with PS, and why I haven’t passed it on to any of my 13 children and grandchildren (“touch wood”), whilst other families include many with this affliction. I’ve been annoyed that there seems to be so little research into the causes and prevention of PS and similar conditions that trouble new parents and their babies. But I’m increasingly realising how complex this branch of science is, and intrigued by the technology that is steadily unlocking some of the mysteries.
Another journal article I read recently defines some terms helpful to understanding the causes of conditions like the ones covered by this post. The article states: Polygenic traits are determined by the combined effects of many genes. Multifactorial traits are determined by several genes and environmental factors. It is now believed that the majority of inherited traits are multifactorial or polygenic.
An associated journal article calls PS a threshold multifactorial trait. If a woman has PS, she or her parents have abnormal genes or more risk factors (a higher threshold) than is usually necessary to produce PS in males, and her children therefore have a higher risk of the PS recurring. The affected woman’s male children have the highest risk as they will inherit more than the usual number of susceptibility genes and also because they are the more sensitive sex.
All this means that we can know all there is to know about my gene profile, like my parents have no PS on either side of the family, and still have a child with this condition. And there are several stories on the web of both parents having had PS and their children not.
Genetics is very humbling and uncertainty is very frustrating for control freaks. But provided we are sober about our finiteness, the unlocking of more and more of the complex causes of infant surgery is fascinating and reassuring. The world including our bodies is more intricate than we ever imagined, but our empowerment is making progress, sometimes at a frustratingly slow pace, sometimes with amazing speed, but never complete.