Matthew Great scenario's
> 1. If prenatal diagnosis is being done by chorionic villus sampling > (CVS) in a twin pregnancy (which does happen) then it is the placenta > - or rather the placentas - which are sampled. Each placenta has a > DNA genotype matching that of the fetus attached to it (ie not the > mother) as the placenta is an extension of the fetus. If however the > fetus is an extension of the mother, then are we really saying we > like the idea that the placentas may have to appear as multiple > "temporary" organs of the mother, which are different in every > pregnancy, and which never share her total genotype? A likely outcome > would be selective termination of one twin (the affected one, on the > basis of a molecular finding and either a makable or a confidently > predictable clinical diagnosis) leaving the unaffected one to go to > term. Thus a part of the mother is diagnosed clinically and > molecularly, findings which are important for the mother later on, in > that they'll trigger appropriate care next time around, but which > *must not* be confused with her own clinical diagnoses or test > results. This example is a very good one - it shows that there is a need to identify the fetus over and above its relationship with the mother. I have suggested that we use a local label for this - could be LOCAL:Twin1_2002. - the relationship for the information is FETUS. The important thing here is that we have the idea of subject of care - a unique identifier (or self) and the relationship. The sampling is the taking of a histological sample of a body part - the subject is the FETUS. There will be a procedure record, a sample and a histological report - all with the fetus as the subject of care for the data - in a composition that is part of the mothers EHR. It may be copied to the child's EHR in the future - I have thought about the transform required to do this and it should be relatively easy if the relationship of the two records is stated first. > 2. Bone marrow transplantation, where it may be necessary to > distinguish that the post-transplant patient may still have a > haemoglobin variant, but a different one to the one they were treated > for, and accordingly no disorder to go with it, but will still be > genetically as they were before the treatment in every other organ. > Also the donor was most probably selected from the same family, so > confidentiality may be slightly different...? Interesting - who is the subject of care then? I guess this will be deduced from the data - I do not think that we can say the origins of all the states in a person that arise following a donation - at times it may be ambiguous (graft v host). We have considered 'donor' to be the relationship - but the person may have a relationship with the person apart from this? I do not think that the subject of care needs to be the donor then - it can be the family member as it is known who they are. Interesting! > It seems to me that we can either organise our concepts to make this > kind of record easier and more obvious, or we can begin to inbuild > problems for later on (eg if the fetus is part of the mother, having > to explain to all our knowledge agents that this might not extend to > genotypes, or if it does, then by chance rather than biological > imperative etc...). In the event of one of two fetuses being > affected, and one pregnancy being terminated, what is the result in > the record to indicate the original number of conceptions, the fact > that a genetic risk actually produced a fetus with a prospective > problem, and the DNA and other data originated in the process of the > testing of the CVS sample? It would be wrong, I feel, to treat the > fetus' diagnosis as one of the mother, as confusion here could lead > to all kinds of erroneous conclusions (one fetus had sickle cell -> > mother - who is actually just a carrier - has sickle cell...?). I do believe that we have this covered - the donor example is a bit of a mind bender but I think the subject of care and relationship provides the solution. COmments? Cheers, Sam ____________________________________________ Dr Sam Heard Ocean Informatics, openEHR Co-Chair, EHR-SIG, HL7 Chair EHR IT-14-2, Standards Australia Hon. Senior Research Fellow, UCL, London 105 Rapid Creek Rd Rapid Creek NT 0810 Ph: +61 417 838 808 sam.heard at bigpond.com www.openEHR.org www.HL7.org __________________________________________ - If you have any questions about using this list, please send a message to d.lloyd at openehr.org
