Cytogenetic and molecular genetic analysis of a case with mosaic marker chromosomes / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the source of small supernumerary marker chromosome in a case.</p><p><b>METHODS</b>G-banded karyotyping, fluorescence in situ hybridization, multiple sequence tagged sites (STS) of the Y chromosome, and Illumima Human Cyto SNP-12 Beadchip analysis were carried out.</p><p><b>RESULTS</b>The karyotype was mos 46,X,+mar1[21]/46,X,+mar2[78]. Y chromosome STS analysis has displayed the presence of sy84, sY86, USP9Y and DDX3Y genes from the AZFa region, and sY1227 of the AZFb region, while sY1228, sY1015, sY127, sY134 from the AZFb region, and sY254 and sY255 from the AZFc region were missing. FISH analysis has verified both of the marker chromosomes to be Y chromosome fragments. Mar1 was ish.idic(Y)(q11.2)(SRY++,DXZ1+,DYZ3++,DYZ1-), while mar2 was ish.del(Y)(q11.2)(SRY+,DXZ1+,DYZ3+,DYZ1-). Single nucleotide polymorphism (SNP) microarray analysis showed that the Yq11.2-Yq12 has lost a 10.81 Mb fragment.</p><p><b>CONCLUSION</b>The marker chromosomes were verified to be aberrant Y chromosomes, with the breakage and recombination occurring in Yq11.2. Mar 1 was an isodicentric Y chromosome (idic(Y)pter to q11.2::q11.2 to pter), and mar2 was del(Y)(q11.2). The karyotype was mos 46,X,ish idic(Y)(q11.2)(DYZ3++,SRY++,DXZ1+,DYZ1-)[21]/46,X,ish del(Y)(q11.2)(DYZ3+,SRY+,DXZ1+,DYZ1-)[78]. Combined FISH, Y chromosome STS analysis, SNP microarray analysis and other technologies can facilitate determination of the nature of marker chromosomes.</p>

Genetic diagnosis and analysis of related genes for a pedigree with 2p25 and 12p13 cryptic rearrangements / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze chromosome aberration in a child with mental retardation and abnormalities and its parents.</p><p><b>METHODS</b>Chromosome G banding, multiplex ligation-dependent probe amplification, fluorescence in situ hybridization and single nucleotide polymorphisms array were employed for analysis.</p><p><b>RESULTS</b>Karyotype analysis revealed that the child was 46,XX and the father was 46,XY, while the mother was 46,XX, add (12)(p13). Subtelomeric region analysis with MLPA displayed that the child has reduced ACP1 gene copy number in 2p25 region and increased SLC6A12,KDM5A gene copy numbers in 12p11 region. SNP-array has fine mapped the duplication to 12p13.33-p12.3, a 15.142 Mb region, and a deletion to 2p25.3 for 3.194 Mb, which resulted in duplication of 9 genes including SLC6A12 as well as deletion of 11 genes including SNTG2, respectively. FISH analysis revealed that the child was 46,XX,ish,der(2),t(2;12)(p25;p13)mat, or partial monosomy 2p25 and partial trisomy 12p13. In addition,the mother was a carrier with cryptic balanced translocation chromosome, 46,XX,isht(2;12) (p25;p13). Mental abnormalities and retardation of the child may be attributed to heterozygous deletion of SNTG2, MYT1L genes and duplication of SLC6A12 gene.</p><p><b>CONCLUSION</b>Combined use of MLPA, FISH and SNP-array can facilitate accurate diagnosis of cryptic rearrangement at genomic level.</p>

Breakpoint localization of Y-chromosome massive deletions in 49 spermatogenesis dysfunction patients / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze the characteristics of azoospermia factor(AZF) deletions in Y-chromosome.</p><p><b>METHODS</b>Based on the AZF microdeletion screening on 272 cases of azoospermia and 240 cases of severe oligozoo spermia, 49 cases were investigated using 23 sequence-tagged sites (STS) in AZFa, AZFb and AZFc. For some cases, single nucleotide rarians (SNV) method was applied to identify the single nucleotide polymorphism (SNPs) in four DAZ gene copies and to determine the copy number of the DAZ gene.</p><p><b>RESULTS</b>In 6 cases with deletions of AZFb+c, there was 1 case with sY98/sY1206 deletion, 4 cases with P5/distal-P1 recombination and 1 with P4/distal-P1 recombination. In 3 cases with deletions in AZFb, 1 case showed P5/P3 deletion and 2 cases showed P5/proximal-P1 recombination with DAZ1 and DAZ2 deletions. b2/b4 recombination was observed in all the 40 cases with deletions in AZFc. A fraction of patients with AZFb and AZFb+c deletions showed oligospermia and spermatogenic failure by testicular biopsy.</p><p><b>CONCLUSION</b>Breakpoint localization of deletions in AZF regions may help elucidating the mechanisms of microdeletions, and analysis of the characteristics and quantity of deleted genes essential for normal spermatogenesis may evaluate the association of phenotype with spermatogenic failure.</p>