Abstract
In a recent study Bugge etal1 and Kotzot etal2 reported that isochromosomes 18p originate mainly from maternal meiosis II nondisjunction, followed by misdivision. In order to determine if there is a common mechanism for isochromosome formation, three cases with mosaicism for an additional isochromosome 12p and three cases with tetrasomy 9p were studied. Two probands with isochromosomes 12p and the three cases with isochromosome 9p showed 3 alleles (two different maternal alleles and one paternal allele) at several loci mapping to distal 12p and 9p, respectively. Maternal heterozygosity for distal markers was reduced to homozygosity for markers closer to the centromere in both i(12p) cases and in one i(9p) case. For one patient with isochromosome 12p, the maternal band was clearly stronger than the paternal one at some loci, but two distinct maternal alleles were never seen. For one foetus and the patient with tetrasomy 9p, distal markers showed maternal heterozygosity. All proximal markers were not informative in these two i(9p) cases. Our findings indicate common features in different autosomal isochromosomes: the origin of the isochromosomes analysed is predominantly maternal; and a common mechanism appears to underlie their formation, namely due to meiosis II nondisjunction followed by a rearrangements leading to duplication of the short and loss of the long arm.
Similar content being viewed by others
Article PDF
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Dutly, F., Balmer, D., Baumer, A. et al. Isochromosomes 12p and 9p: parental origin and possible mechanisms of formation. Eur J Hum Genet 6, 140–144 (1998). https://doi.org/10.1038/sj.ejhg.5200168
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/sj.ejhg.5200168
Keywords
This article is cited by
-
A high level of tetrasomy 9p mosaicism but no clinical manifestations other than moderate oligozoospermia with chromosomally balanced sperm: a case report
Journal of Assisted Reproduction and Genetics (2020)
-
Prenatal diagnosis of Pallister–Killian syndrome in young woman: ultrasound indicators and confirmation by FISH
Archives of Gynecology and Obstetrics (2009)
-
Partial tetrasomy 12pter-12p12.3 in a girl with Pallister-Killian syndrome: extraordinary finding of an analphoid, inverted duplicated marker
European Journal of Human Genetics (2001)