[Delineation of three structural Y chromosome aberrations combined molecular techniques]

Abstract

Objective: To delineate the structure of Y chromosome aberrations and recombinant mechanisms for three patients.

Methods: Karyotype analysis, multiplex ligation dependent probe amplification (MLPA), fluorescence in situ hybridization (FISH), Y chromosome sequence tagged sites (STS) analysis, human whole genome-wide SNP array were used.

Results: The karyotypes of the three patients were 46, X, +mar. As suggested by MLPA analysis, case 1 has increased copy numbers of SRY, ZFY and UTY genes, case 2 had increased copies of SRY and ZFY genes, and deletion of UTY gene, and case 3 had decreased copies for subtelomeric regions of X/Yp and X/Yq. By STSs analysis, case 1 has retained SRY, sY84 and sY86 in the AZFa region, sY1227 in the AZFb region, whilst lost sY1228 in the AZFb region and other STSs in the AZFc region. Its breakpoint was thereby mapped between sY1227 and sY1228. Case 2 has retained SRY and sY1200 in the centromeric region, whilst has deletion of other STSs. Case 3 has retained SRY and STSs in the AZF regions. By SNP array, case 1 had duplicated Yp11.31-p11.2 and deletion of Yq11.22-q11.23 (approximately 5.18 Mb). Case 2 had duplicated Yp11.31-p11.2 and deletion of Yq11.21-q11.23 (approximately 14.644 Mb). Case 3 had single copy number deletion of p22.33 and q28 in the subtelomeric region of X/Yp and X/Yq. By FISH, cases 1 and 2 showed two signals for SRY and DYZ3 but no signal for DYZ1 on their marker chromosomes. Combining above results, the karyotypes of cases 1, 2 and 3 were determined as 46, X, idic(Y) (q11.23), 46, X, idic(Y) (q10) and 46, X, r(Y) (p11q12), respectively.

Conclusion: Y chromosome aberrations are variable. Combined use of MLPA, STSs, FISH and SNP array is effective for revealing the breakpoints and recombinant mechanisms.