So today I stumbled across a report composed by Devin M Cox and Merlin G Butler which is detailed and linked below...
The 15Q11.2 Microdeletion: A Review
This I found to be quite a tough read and struggled to form an understanding of some elements of it, so I felt that this would be a great platform, and opportunity to lay out my understanding of this and seek clarity on some of the points discussed.
Ok, here goes nothing... The report begins by laying out the primary components of the disorder and state that the carrier will be within the “... susceptibility region for neurological dysfunction with general developmental and motor delay with speech problems...”. Whilst they go on to stipulate that there is no clear dysmorphc phenotype (which I read to understand as no specific physical presentation) the following dysmorphic features have been noted in conjunction with the deletion........
*Hypertelarism (increased distance between organs or bodily parts - such as eyes);
*hypotelarism (decreased distance between organs or bodily parts - such as eyes);
*Plectus Exvactu (No not a Harry Potter spell as I fist suspected but a deformity to the sternum and rib cage);
*Plagiocephaly (also known as flat head syndrome);
*Contractures (the shortening and hardening of muscle).
So quite a list of physical features that have been seen in people with the deletion BUT I imagine (not stated in the literature) not necessarily unique to this deletion, meaning that just because someone might present with any combination of the features it doesn’t mean that they have the deletion and vice versa.
The literature also goes on to state that a FSIQ (Full Scale Inteligence Quotient) score or assessment of 75 or less is deemed to be “special education” which may (possibly) result in the following features in the carrier (although they suggest that more study is required to ensure that these are definitively associated findings);
*Writting difficulties (60% of those in the study);
*Reading difficulties (57% of those in the study);
*Memory problems (60% of those. In the studies);
*Low verbal IQ of below or equal to a score of 75 (50% of those in the studies)
Performance IQ however stood out to me as quite high as they indicate that only 33% of the study group scored 75 or below. Indicating that actually 67% scored above 75.
They go on to list behavioural and psychiatric problems as follows;
*ASD (Autistic Spectrum disorder) (27% of the study group);
*Schizophrenia or paranoid psychosis (20% of the study group);
*(ADD) Attention Deficit Disorder sometimes know as ADHD (35% of the study group);
*Obsessive Compulsive Disorder - or OCD (26% of the study group);
* Self injurious (26% of the study group);
*Oppositional Defiance Disorder - Is this the same as PDA? (24% of the study group);
*An unusually happy expression (12% of the group);
*Anxiety (6% of the study group).
They go on to state that there is a significant Association between those with this deletion and schizophrenia (0.64%) according to the results of a separate study. In addition to this they move on to state that they have .... “found a small risk regarding this deletion and autism.”
So at this point I am struggling to understand how they have at one point stated that 27% of a study group has an Autistic Spectrum Disorder and that this is a “small risk” yet 0.64% of another study group were found to have schizophrenia and that is described as “significant”. I am very much strugggling to get my head around that one.
Reading on through this piece of literature Cox and Butler go on to talk about other related medical concerns associated with the 15q11.2 microdeletion and list them as;
*Abnormal brain imaging (43% of the study group);
*Siezures or epilepsy (27% of the study group);
*Ataxia or balance problems (28% of the study group);
*Congenital heart defect (9% of the study group);
*Genital abnormalities (7% of the study group);
*Recurrant infections (7% of the study group);
*Cataracts (4% of the study group);
*Hearing loss or impairment (4% of the study group);
*Tracheoesophageal Fistula - an abnormal connection between esophagus and the trache (2% of the study group);
*Omphalocele - an intestinal birth defect (2% of the study group).
Again what I read into this is that just because you have the deletion it does not necessarily follow that you will have these medical conditions at all, and likewise just because you have one, or a combination, of these medical conditions it does not mean to say that you have the deletion.
They conclude with stating that “Clinically neurological dysfunction, developmental and language delay are the most commonly associated findings, followed by motor delay, ADD/ADHD, and autism spectrum disorder showing incomplete penetrance and variable expressivity...The 15q11.2 BP1-BP2 microdeletion Syndrome has a reported de novo frequency between 5% - 22%, 51% having inherited the microdeletion from an apparently unaffected parent and 35% having inherited the deletion from an affected parent.”
So I am reading this as if a person has the deletion that there is a 51% chance that they themselves inherited the deletion from a parent before them and that there is a probability that it has been handed down through a number of generations, and that this pattern of continuing to pass it down stands at 51%.
So this in itself would be a prompt for me to point out to siblings and cousins that should there children be demonstrating issues with learning, behaviour, and or other medical conditions already mentioned in this report - they may well be advised to seek a micro array test to rule out the 15q11.2 bp1-bp2 Syndrome.