Dear All, Just a couple of use cases for the discussion:
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. 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...? 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...?). Just some thoughts! Yours, Matthew On 16 Dec 2002, at 5:45, Thomas Beale wrote: > > I am forwarding this to the list, since I think this is an important > discussion. > > Sam Heard said: > > Tom > > > > The donor is definitely anonymous in most settings. The fetus can be > part of the mother - this is a bit like the local terminologies in > archetypes - we need a way of saying that the relationship is the only > defining feature and there is no ID. > > > > Cheers, Sam > > > > -----Original Message----- > From: Thomas Beale [mailto:thomas at deepthought.com.au] > Sent: Thursday, 12 December 2002 6:43 PM > To: Sam Heard > Subject: Re: Subject of care > > > > Sam Heard wrote: > > >Dear Tom > > > >Just checking that we can enter a subject or a subject relationship > >or both as invariants. Fetus and Donor probably are subject > >relationships as there is no person_ID. > > > there should be a person id - why would there not be a person id > for a donor? Is it because donor's are anonymous? Does this mean > that even the PMI or whatever has no idea who the donor is? If so, > we need a special "anonymous" or "anonymous donor" concept in the > demographic system to model this properly. > > For a foetus, it may be the mother, if we consider that for some > time the mother is the subject and the foetus the "part_ of the > subject" being documented. Else we have to have a better theory of > id creation. > > - t > > > > > - > If you have any questions about using this list, > please send a message to d.lloyd at openehr.org > -- "Mr. Matthew Darlison BA MA" <M.Darlison at ucl.ac.uk> Senior Research Fellow, Clinical & Applied Bioinformatics UCL Centre for Health Informatics and Multiprofessional Education (CHIME) APoGI on the Web at http://www.chime.ucl.ac.uk/APoGI/ - If you have any questions about using this list, please send a message to d.lloyd at openehr.org
