The inversion of heterochromatic region of chromosome 9 (human) is considered a normal variant, but some author are not agree. I mean inv 9 (p11,q13) or inv 9(p11,q12)
we can say no deleterious effect at least for the time being
May be there are unknown effects that can be discovered in the future
until this moment I did not find scientific evidence to demostrate the deleterious effect of this inversion, but I have read publications that associate this chromosomic variant to some kind mental disorder, abortions or another kind of mental retardation. I appreciate very much your answers
luis
luis, you should see the prestige of journals to show this publications
sometimes its associated with mental disorders or abortions. u should think of micro array to see other variables
According to my clinical inv(9) patient,I should say it is associated with aboration and subfertility.
And, G-banding is not enough to make the phenotype to genotype analysis.
Xie I appreciate your experience, but Do you know some report about this chomosomal 9 variant that was analice with CGH microarray, and the authors found any thing wrong?
luis
The inversion of heterochromatic region of chromosome 9 human, inv 9 (p11,q13) or inv 9(p11,q12) is a normal variant, no deleterious effect.
No solid evidence so far.
And microarrays will not solve the question because this paracentric heteriochromatin, is not represented in the commercial microarrays.
so no solid evidence as say Camargo. in my opinion you have a patient with a problem (abortions, mental disorders, subfertility etc ) and you only find the heterocromatin inversion 9, you dont have other option to diagnosis and you say well should be this inversion. But I do not find a scientific evidence.
Inversion 9 involving 9p12 and 9q13-21.1 are constitutional and non pathogenic. For details you can read EJHG (2002) 10, 790-800.
Luis, as you say : "you have a patient with a problem (abortions, mental disorders, subfertility etc ) and you only find the heterocromatin inversion 9, you don't have other option to diagnosis and you say well should be this inversion." In this case, abortions and subfertility may be associated with chromosomal inversion, it is not only for chromosome 9 but also for other chromosomes, because of inversion effect. However, for mental disorders is not because of heterocromatin inversion 9.
While some authors observed an increased risk of pregnancy with trisomy 21 in carriers of inv(9) that contains additionally an enlarged heterochromatin region. Those findings suggest that heterochromatin took part in crossing-over. It could result in aberrant chromosomes after crossing-over.
The de novo inv (9) may carry adverse fetal growth factor, and inherited inv (9) is also could occur small unbalance chromosomal rearrangement in the genome during the transfer of parental gametes which cannot be detected by G-banding.
In my clinical experience, I did meet some patient with mental disorders in carried with heterocromatin inversion 9.But most of these patient also with other abnormity which cannot be detected by G-banding , such as microdeletion or microduplication detected by CMA, gene mutation detected by sequence.
As a result, I intended to say that patient with heterocromatin inversion 9 has a high risk of abortions and subfertility but not mental disorders.
Dear Yingjun Xie
May these patients have another factors that passed undiagnosed ?
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