We report on a novel variant of the dicentric chromosome 17;20 (dic (17;20)(p11.2;q11.2) in a patient with de novo myelodysplastic syndrome (MDS). Based on FISH and array-CGH, the variant turns out to be an insertion of chromosome 17 (17p11.2-telomere 17) into chromosome 20 with breakpoints at 20q11.22 and 20q13.33. Based on conventional chromosome analysis and G-banding patterns, the region 17p11.2-17q25 was directly inserted between 20q11.22 and 20q13.33. The breakpoint junctions occurred within KCNJ12 (17p11.2), UQCC1 (20q11.2), and CDH4 (20q13.3), leading to 5′ deletions of all the genes and positioning the 3′ of UQCC1 next to KCNJ12 at 17p11.2 and CDH4 next to an unknown gene at 17q25-20q13.3. In addition, the centromere of chromosome 17 was not active, transforming the primary constriction to a flat band. Therefore, the novel insertion variant is a pseudo dicentric derivative chromosome with one functional centromere: 45,XX,der(17;20)del(20)(q11.22q13.33)ins(20;17)(q11.2;p11.2q25). A review of the literature of all dic(17;20) cases is presented. For the first time, we report an array-CGH characterization of such rare variant that revealed to be an insertion.

中文翻译：

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以 Array-CGH 为特征的罕见畸变 dic(17;20)(p11.2;q11.2) 的新变体重排，作为多系发育不良骨髓增生异常综合征 (MDS-MLD) 患者的插入

新的插入变体是具有一个功能性着丝粒的假双着丝粒衍生染色体：45,XX,der(17;20)del(20)(q11.22q13.33)ins(20;17)(q11.2;p11.2q25 ）。介绍了所有 dic(17;20) 案例的文献综述。我们第一次报告了这种罕见变异的阵列-CGH 表征，该变异显示为插入。