[Cytogenetic and molecular genetic study of a case with 8p inverted duplication deletion syndrome].
OBJECTIVE
To define the origin and the precise location of the aberrant fragments on the short arm of the chromosome 8 in a mentally retarded boy, and to understand the mechanism, the characteristic clinical features and the recurrent risk associated with this abnormality.


METHODS
High-resolution chromosomal banding was performed to analyze the karyotype of the patient and his parents, array comparative genomic hybridization (array-CGH) was employed to investigate the precise location of the aberrant fragments, and quantitative real-time PCR was used to confirm the results.


RESULTS
The rearranged chromosome 8 in the patient was inverted and duplicated for region 8p11.2-p23.1, and deleted for region 8p23.1-pter. In between, a 5.70 Mb single copy region was present, which was delimited by the two olfactory receptor (OR) gene clusters.


CONCLUSIONS
This is a case of classic inv dup del(8p) syndrome, which is characterized by severe mental retardation, brain malformation and specific facial dysmorphism, and is induced by non-allelic homologous recombination (NAHR) between the OR genes on 8p23.1. Prenatal diagnosis should be performed to monitor the recurrent risk of inv dup del(8p), as well as the other three harmful consequences resulted from the same NAHR mechanism. To the best of our knowledge, this is the first case of inverted duplicated 8p syndrome identified in Mainland China.
Han
Xu
X
Cytogenetic Department of Shanghai Institute for Pediatric Research, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, 200092 PR China.
Zhang
Jing-min
JM
Jiang
Wen-ting
WT
Hu
Qin
Q
Tao
Jiong
J
D000015:Abnormalities, Multiple / Q000235:genetics*; D002681:China; D002869:Chromosome Aberrations / Q000145:classification*; D002871:Chromosome Banding / Q000379:methods*; D002872:Chromosome Deletion; D007446:Chromosome Inversion; D002874:Chromosome Mapping; D002898:Chromosomes, Human, Pair 8; D020732:Cytogenetic Analysis / Q000379:methods*; D003582:Cytogenetics / Q000379:methods; D020440:Gene Duplication; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D007621:Karyotyping / Q000379:methods; D008297:Male; D005810:Multigene Family; D013577:Syndrome