Unterberger Iris, Dobesberger Judith, Schober Harald, Krabichler Birgit, Lamina Claudia, Schatz Ulrich, Zschocke Johannes, Luef Gerhard, Kotzot Dieter, Fauth Christine
Department of Neurology, Innsbruck Medical University, Anichstraße 35, A-6020 Innsbruck, Austria.
Department of Neurology, Innsbruck Medical University, Anichstraße 35, A-6020 Innsbruck, Austria; Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University of Salzburg, Ignaz-Harrer-Straße 79, A-5020 Salzburg, Austria.
Eur J Med Genet. 2019 Nov;62(11):103564. doi: 10.1016/j.ejmg.2018.10.016. Epub 2018 Oct 29.
Ring chromosome 20 syndrome is a rare chromosomal disorder characterized by childhood-onset drug-resistant epilepsy, behavioral problems and variable cognitive impairment. While most cases occur sporadically, parent-to-child transmission of ring 20 mosaicism has only been reported in a few exceptional families. We identified a further family with mother-to-child transmission of ring 20 mosaicism. Detailed characterization of the ring chromosome showed a complete ring with preserved telomere repetitive sequences. SNP genotyping excluded mosaic uniparental disomy and indicated that the chromosome was transmitted without recombination from mother to child. These results corroborate the findings of a previous study and support the hypothesis that inherited mosaicism is due to transmission of an unstable chromosome either prone to ring opening or to ring re-formation.
20号环状染色体综合征是一种罕见的染色体疾病，其特征为儿童期起病的耐药性癫痫、行为问题和可变的认知障碍。虽然大多数病例为散发性，但20号环状染色体嵌合体的亲子传递仅在少数特殊家庭中有报道。我们又发现了一个20号环状染色体嵌合体母婴传递的家庭。对环状染色体的详细特征分析显示为一个完整的环，端粒重复序列得以保留。单核苷酸多态性基因分型排除了嵌合单亲二体，并表明该染色体从母亲传给孩子时未发生重组。这些结果证实了先前一项研究的发现，并支持以下假说：遗传嵌合体是由于一条不稳定的染色体传递所致，该染色体易于开环或重新形成环。
