Betz Jaime L, Behairy Ahmed S, Rabionet Pedro, Tirtorahardjo Budi, Moore Mathew W, Cotter Philip D
Division of Genetics, US Labs Inc., Irvine, CA, USA.
Cancer Genet Cytogenet. 2005 Jul 1;160(1):76-8. doi: 10.1016/j.cancergencyto.2004.12.002.
Pericentric inversion of the heterochromatic region of chromosome 9 [inv(9)] is a common heteromorphism in the general population. It is presumed familial as there are no reports of de novo inv(9) chromosomes in constitutional karyotypes. We report 2 cases of acquired inv(9) chromosomes; 1 patient with acute myeloid leukemia, 46,XY,inv(9)(p11q13)[11]/46,XY[9], and a second with severe anemia, 46,XX,inv(9)(p11q13)[14]/46,XX[6]. The acquired nature of the inv(9) was confirmed by constitutional karyotyping and/or molecular analysis. The inv(9) in these patients may be a de novo inversion that cytogenetically mimics the constitutional inv(9) heteromorphism. Alternatively, it may be the result of neocentromere activation in 9q due to epigenetic events associated with the disease in these patients that results in a metacentric chromosome similarly mimicking the constitutional inv(9). One previous report of an acquired inv(9) was in a patient with essential thrombocythemia. The differences in clinical presentation may represent different underlying mechanisms generating the inv(9). The significance of an acquired inv(9) is unknown and will require reporting of additional cases.
9号染色体异染色质区的臂间倒位[inv(9)]在普通人群中是一种常见的异态性。由于在染色体组型中没有新发inv(9)染色体的报道，因此推测其具有家族性。我们报告了2例获得性inv(9)染色体病例；1例急性髓系白血病患者，核型为46,XY,inv(9)(p11q13)[11]/46,XY[9]，另一例严重贫血患者，核型为46,XX,inv(9)(p11q13)[14]/46,XX[6]。通过染色体组型分析和/或分子分析证实了inv(9)的获得性。这些患者中的inv(9)可能是一种新发倒位，在细胞遗传学上模拟了染色体组型inv(9)异态性。或者，它可能是由于这些患者疾病相关的表观遗传事件导致9号染色体长臂新着丝粒激活的结果，从而产生一条类似染色体组型inv(9)的中着丝粒染色体。之前有一篇关于获得性inv(9)的报道，是在一名原发性血小板增多症患者中。临床表现的差异可能代表了产生inv(9)的不同潜在机制。获得性inv(9)的意义尚不清楚，需要报告更多病例。
