Is there a yet unreported unbalanced chromosomal abnormality without phenotypic consequences in proximal 4p?
Unbalanced chromosomal abnormalities (UBCA) are reported for >50 euchromatic regions of almost all human autosomes. UBCA are comprised of a few megabases of DNA, and carriers are in many cases clinically healthy. Here we report on a partial trisomy of chromosome 4 of the centromere-near region of the short arm of chromosome 4 present as a small supernumerary marker chromosome (sSMC). The sSMC was present in >70% of amnion cells and in 60% of placenta. Further delineation of the size of the duplicated region was done by molecular cytogenetics and array comparative genomic hybridization. Even though the sSMC lead to a partial trisomy of ~9 megabase pairs, a healthy child was born, developing normally at 1 year of age. No comparable cases are available in the literature. Thus, we discuss here the possibility of having found a yet unrecognized chromosomal region subject to UBCA.
Liehr
T
T
Jena University Hospital, Institute of Human Genetics, Kollegiengasse 10, Jena, Germany. i8lith@mti.uni-jena.de
Bartels
I
I
Zoll
B
B
Ewers
E
E
Mrasek
K
K
Kosyakova
N
N
Merkas
M
M
Hamid
A B
AB
von Eggeling
F
F
Posorski
N
N
Weise
A
A
D002869:Chromosome Aberrations; D002894:Chromosomes, Human, Pair 4; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping