Cytogenetic and molecular genetic analysis of the amniotic fluid cells of a fetus with pseudodicentric isochromosome 22 resulting in partial tetraploidy of 22q / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To diagnose chromosomal abnormalities in amniotic fluid cells by combining karyotyping and single nucleotide polymorphism array (SNP-array) analysis, and to explore the application of SNP-array in routine clinical practice.</p><p><b>METHODS</b>Conventional G banding was used to karyotype a fetal amniotic fluid sample and the corresponding peripheral blood samples from the parents, followed by SNP-array analysis of the fetal genomic DNA from the amniotic fluid.</p><p><b>RESULTS</b>The karyotype of the amniocytes was 47, XX, +mar. The marker chromosome was further identified as psu idic (22) (q11.2) by SNP-array analysis, revealing tetraploidy of a 1.7 Mb fragment in 22q11.1-q11.2 interval that involves the critical region for Cat eye syndrome.</p><p><b>CONCLUSION</b>A rare chromosomal abnormality was identified by combining conventional G banding and SNP-array. The high resolution SNP-array could provide more detailed information for determining the origin of chromosomal abnormalities.</p>

Molecular and cytogenetic study on 5 cases with gonadal dysgenesis: clinical applications of fluorescence in situ hybridization(FISH) and BAC-FISH / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the applications of fluorescence in situ hybridization (FISH) in the diagnosis for the patients with gonadal dysgenesis.</p><p><b>METHODS</b>After routine gynecologic examination, ultrasonography and endocrine examination, 5 cases of gonadal dysgenesis and hypogonadism were analyzed by using chromosomal diagnoses including G-banding, Q-banding, multiplex FISH and BAC-FISH analyses.</p><p><b>RESULTS</b>Among the 5 cases of gonad agenesis patients, 2 were pure gonadal dysgenesis with 46, XY karyotype, 3 were mixed gonadal dysgenesis with mos 45, X/47, XXX; 45, X/46, XY or 46, X, der(Y) karyotype.</p><p><b>CONCLUSION</b>Sex chromosomal abnormalities resulted in gonadal dysgenesis symptoms. Applications of FISH and BAC-FISH analyses can correctly diagnose the sex chromosomal abnormalities for patients with gonad agenesis and provide accurate medical genetic data for clinical diagnosis and therapy.</p>