nsuyeda at aol.com on 29-Sept-95 writes:
>A friend's amniocentesis shows an abnormal wide band on six. The lab's
>first response is to .......
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This is regarding your question about your friend's amniocentesis. There is a
question I would have for you (or her). If they are normal, healthy parents
with a normal sonogram why have they had an amnio? I am going to assume the
answer to this is because of the mother's age.
You say there is a band that is wider than normal. (It would help immensely
to know which band). This basically means there is extra DNA present. There
are 2 possibilities:
1) The extra DNA does not contain any genes (nor affect any genes normally
present in this region). There would most likely be no repercussions to the
baby. The only way of knowing this for sure is if one of the parents has the
same anomaly. That is why the first thing the lab is doing is to test the
parents.
2) The extra DNA contains genes. If this is the case then the baby has one
too many copies of the extra gene(s). Because a chromosome analysis is
looking for gross chromosomal abnormalities, the fact that they have found
something means that there is a lot of extra DNA. This is not good news.
To do any kind of research you would have to know the specific band on
chromosome 6 that is affected and then go to a medical library (most
universities have one). You would then have to check the literature to see if
there are any reported cases of people having extra DNA (trisomy) in this
band.
To date 23 patients with partial trisomy of the long arm of chromosome 6 have
been reported. These all involve duplication of more than a single band so
are more severe than what you say is a single abnormal wide band. Therefore it
is impossible to speculate on your case.
The best news would be for one of the parents to have the same phenomenon.
Otherwise, I feel there may very well be physical and/or neurological
problems.
Hilary Taylor
(MSc Human & Medical Genetics)
