Molecular cytogenetic characterization of ring chromosome 15 in three unrelated patients.
We report molecular cytogenetic characterization of ring chromosome 15 in three unrelated male patients with the karyotype 46,XY,r(15). One was a stillborn child with several malformations, and the other two cases showed pre- and postnatal growth retardation and developmental delay, common features for ring chromosome 15 syndrome. One of these patients also displayed clinical features resembling Prader-Willi syndrome (PWS). To delineate the extent of the deletion on chromosome 15, we have carried out fluorescence in situ hybridization (FISH) using bacterial artificial chromosomes (BACs) mapping to the distal long arm of chromosome 15. The deletion breakpoints clustered within a 4.5-6.5 Mb region proximal to the 15q telomere. Two deletions involved the same known genes, while the largest deletion observed in the stillborn child involved three additional genes, including the COUP-TFII gene, which has been suggested to play a role in heart development. The heart malformations, which are observed in this patient, are thus likely to be due to hemizygosity/haploinsufficiency of the COUP-TFII gene. In all three patients, the insulin-like growth factor I receptor gene (IGF1R) gene was deleted supporting the association between IGF1R and growth retardation seen in ring chromosome 15 syndrome.
Tümer
Z
Z
Wilhelm Johannsen Centre for Functional Genome Research, Department of Medical Biochemistry and Genetics, The Panum Institute, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen, Denmark. zeynep@imbg.ku.dk
Harboe
T L
TL
Blennow
E
E
Kalscheuer
V M
VM
Tommerup
N
N
Brøndum-Nielsen
K
K
D000015:Abnormalities, Multiple; D000328:Adult; D002884:Chromosomes, Human, Pair 15 / Q000235:genetics*; D005260:Female; D005317:Fetal Growth Retardation / Q000235:genetics*; D017353:Gene Deletion; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007231:Infant, Newborn; D007621:Karyotyping; D018895:Microsatellite Repeats; D011247:Pregnancy; D011256:Pregnancy Outcome; D012303:Ring Chromosomes