Clinical And Cellular And Molecular Genetics Two Cases Of Chromosome Copy Number Abnormalities In Patients

OBJECTIVES:To investigate the molecular genetic characteristics of two patients with abnormal phenotype caused by novel chromosomal and copy number.Methods and Results:The karyotype of the patient A was analyzed by G-banding and fluorescent in situ hybridization (FISH), and the changes of chromosome copy number were demonstrated by CytoScanTM HD array. The karyotype of the patient A was identified as46,XY,t(1;5;12;13),(1qterâ†'1p33::5q34â†'5qter;5pterâ†'5q31.1::12q24.1â†'12qter;12pterâ†'12q15::13q22â†'13qter;13pterâ†'13q22::12ql5->12q24.1::5q31.1â†'5q34::1p33â†'1pter),der(17)t(16,17)(17pterâ†'17q25::16q24.1â†'16qter).arr16q24.1q24.3(85,805,704-90,155,062)×3. The chromosome rearrangements of the patient A involving chromosomes1,5,12, and13with six different breakpoints are the same as his phenotypically normal mother. A de novo derivative chromosome17is present in the patient, resulting in duplication of the16q24.1q24.3region, which could have an important role in the novel phenotype, including developmental delay,intellectual disability. However, the cause of osteochondromatosis is still unknown.The karyotype of the patient B was analyzed by G-banding and fluorescent in situ hybridization (FISH), and the changes of chromosome copy number were demonstrated by CytoScanTM HD array. The karyotype of the patient B was identified as46, X, pse dic (Y)(p11.32)(Yqteâ†'Yp11.32: Yp11.32â†'Yqter). ish pse dic (Y)(p11.32)(SHOX-, SRY++, DYZ3++). array Yp11.32(PLCXD1-SHOX)×0, Yp11.32q12(SRY-IL9R)×2. The short stature of the patient could be due to the excalation of the short arm end of Y chromosome and the haploinsufficiency of SHOX gene. The cause of spermatogenic failure of the patient may be associated with aberration in pseudoautosomal region1on the rearranged Y chromosome, which induced the deficiency of X-Y pairing or recombination, and meiosis failed to occur subsequently.Conclusion:Technical progress in recent years has changed the diagnostic algorithm in cytogenetic laboratories and has assisted in the definition of cryptic chromosome rearrangements. Molecular cytogenetic studies, including FISH and whole genomic microarray analysis, facilitate the elucidation of subtle chromosome aberrations and provide information on genotype-phenotype correlation.