[SNP-chip technology for identification of origins for prenatally detected marker chromosomes]

To determine the origin of 1 prenatally detected small supernumerary marker chromosome (sSMC) using SNP-chip technology, and to deduce the underlying mechanism.

The fetal sample was subjected to karyotype analysis. The identified sSMC was subjected to genom wide scan using a SNP microarray chip. The results were validated with fluorescence in situ hybridization (FISH).

The karyotype of the fetus was determined as 46, X, +mar, which was verified by SNP microarray chip analysis as Yp11.2-11.3 duplication, along with loss of Yq11.2 region, FISH analysis has confirmed that the sSMC has derived from the Y chromosome.

The karyotype of the fetus was determined as 46, X, idic(Y) (pter→ p11.2::11.2→ pter). Regional deletion of Yq11.2 has been associated with male azoospermia. SNP chip analysis can exclude minor deletions and duplications with a size of more than 1 Mb, which may be applied for verifying difficult cases as well as microdeletion and duplication syndromes upon prenatal diagnosis.