Duplication of chromosome region 4q28.3-qter in monozygotic twins with discordant phenotypes.
We describe monozygotic twins with partially discordant phenotypes who were found to have a duplication of chromosome region 4q28.3-qter. The duplicated region of chromosome 4 resulted from an unbalanced segregation of a balanced maternal (4;22)(q28.3;p13) translocation. Duplication of the long arm of chromosome 4 has been described in >60 patients; however, it usually results from the unbalanced segregation of a parental balanced translocation and has an associated monosomy. Twenty cases of dup 4q without an associated monosomy have been reported, and this is the only case of dup 4q28. 3-qter. All cases of dup 4q are reviewed, and phenotypic aspects are analyzed. Issues of monozygotic twinning and other birth defects also are addressed.
Celle
L
L
The Division of Human Genetics and Molecular Biology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.
Lee
L
L
Rintoul
N
N
Savani
R C
RC
Long
W
W
Mennuti
M T
MT
Krantz
I D
ID
D002869:Chromosome Aberrations; D002874:Chromosome Mapping; D002894:Chromosomes, Human, Pair 4; D020440:Gene Duplication; D006801:Humans; D007223:Infant; D007621:Karyotyping; D008297:Male; D010641:Phenotype; D018433:Twin Studies as Topic; D014430:Twins, Monozygotic / Q000235:genetics*