Mosaicism and risk prediction in parents of children with de novo variants (MORNOVA)

本申请的目的是用两种分子遗传学方法研究患有由于从头变异导致的严重遗传疾病的儿童的父母中的嵌合现象，从而能够更精确地指示兄弟姐妹的复发风险。到目前为止，受影响的父母已经得到了不到1%至5%的复发风险的一揽子估计。然而，根据新生变异的发展，对于另一个孩子来说，这几乎是零到50%之间。我们已经有了237个受影响家庭的各种组织样本。在这些家族中，将通过纳米孔测序来确定变体的起源（定相），并且将通过具有独特分子标识符（UMI）的靶向组分析来分析两个亲本在不同组织中的嵌合现象。这些结果将与关于新发变异和临床无关变异出现的其他现有数据（来自文献以及我们的队列）一起使用，以计算个体复发风险。此外，这些数据将与小鼠家族中的三外显子组分析相关联和验证。最后，这些结果将纳入临床常规，并从长远来看，纳入对面临新怀孕的侵入性产前诊断问题的夫妇的个人咨询。

The aim of the present application is to investigate mosaicism in parents of children with a severe genetic disease due to a de novo variant with two molecular genetic methods and thus to be able to indicate the recurrence risk for siblings more precisely. Up to now, affected parents have been given a blanket estimate of a recurrence risk of less than 1 to 5 %. However, depending on the development of a de novo variant, this is between practically zero and 50% for a further child. We already have various tissue samples from 237 affected families. In these families, the origin of the variant (phasing) will be determined by nanopore sequencing and both parents will be analysed for mosaicism in different tissues by targeted panel analysis with unique molecular identifiers (UMI). These results will be used with other already available data on the emergence of de novo variants and clinically irrelevant variants (from the literature as well as in our cohort) to calculate the individual risk of recurrence. Furthermore, the data will be correlated and verified with trio-exome analyses in mouse families. Finally, the results will be integrated into the clinical routine and, in the long run, into the individual counselling of couples facing the question of invasive prenatal diagnostics in case of a new pregnancy.