Kosztolányi G, Méhes K, Hook E B
Department of Pediatrics, University Medical School, Pécs, Hungary.
Hum Genet. 1991 Jul;87(3):320-4. doi: 10.1007/BF00200912.
A review of case reports on patients with ring chromosome revealed 30 individuals (plus two fetuses) who inherited the ring from a total of 23 carrier parents (21 mothers and 2 fathers). The proportion of cases with inherited rings, among all patients with a ring, was calculated to be 5.6% as an upper limit. However, because of a propable difference in survival and fertility between individuals with transmitted and do novo rings, and because of the preferential publication of cases involving inherited rings (and thus a publication bias), the proportion of inherited rings should in reality be no more than 1%. Out of 30 transmitted rings, there were 9 where parent and child were both mosaics, suggesting an inherited instability of the chromosome involved leading to de novo re-formation of the ring in the second generation. The relatively mild clinical manifestations of ring chromosomes, in general, was found to be even more striking in familial cases. In half of the offspring the phenotype was very similar to that of the parent. However, in about a third of cases the offspring were more severely (mentally) affected. This fact should be considered in genetic counseling of clinically normal women who carry a ring chromosome.
一项对环形染色体患者病例报告的综述显示，共有30名个体（外加2个胎儿）从总共23名携带者父母（21名母亲和2名父亲）那里遗传了环形染色体。在所有环形染色体患者中，遗传环形染色体的病例比例经计算上限为5.6%。然而，由于携带遗传环形染色体和新发环形染色体的个体在生存和生育能力上可能存在差异，也由于涉及遗传环形染色体病例的优先发表（从而存在发表偏倚），实际上遗传环形染色体的比例应不超过1%。在30个遗传的环形染色体中，有9个亲子双方均为嵌合体，这表明所涉及的染色体存在遗传不稳定性，导致在第二代中环形染色体重新新发形成。一般来说，环形染色体相对较轻的临床表现，在家族性病例中更为明显。在一半的后代中，其表型与父母非常相似。然而，在约三分之一的病例中，后代（智力上）受到的影响更为严重。在对携带环形染色体的临床正常女性进行遗传咨询时，应考虑这一事实。
