Sawyer J R, Rowe R A, Hassed S J, Cunniff C
Department of Pathology, University of Arkansas for Medical Sciences, Little Rock.
Hum Genet. 1993 Mar;91(1):42-4. doi: 10.1007/BF00230220.
High-resolution cytogenetic studies of a normal individual with ring chromosome 19 indicate that, at the late-to-mid prophase level of band resolution, no apparent chromosomal material is missing, and that telomeric fusion/association, not deletion, is the cause of the ring chromosome formation. Sub-band analysis of the telomeric fusion shows thin chromatin filaments between the telomeres of some of the very elongated ring chromosomes, which cannot be resolved by metaphase chromosome analysis. The ring chromosome found in this individual shows evidence of the characteristic instability associated with ring chromosomes, including duplicated segments, double rings, and subsequent loss of the ring resulting in cells with monosomy 19. The lack of phenotypic effect and the unstable ring behavior, unlike previously reported patients with ring 19, support the formation of this ring by telomeric association.
对一名患有19号环状染色体的正常个体进行的高分辨率细胞遗传学研究表明，在带分辨率的晚前期到中期水平，没有明显的染色体物质缺失，并且端粒融合/关联而非缺失是环状染色体形成的原因。对端粒融合的亚带分析显示，在一些非常细长的环状染色体的端粒之间存在细染色质丝，这在中期染色体分析中无法分辨。在该个体中发现的环状染色体显示出与环状染色体相关的特征性不稳定性证据，包括重复片段、双环以及随后环状染色体的丢失，导致细胞出现19号染色体单体。与先前报道的19号环状染色体患者不同，缺乏表型效应和不稳定的环状染色体行为支持了通过端粒关联形成该环状染色体。
