An unusual number of high mutations expand in the male germline in tyrosine kinase receptors

Description

The higher risk of older fathers having an affected offspring with early or late-onset rare disorders has been quite unsettling; but unfortunately, the methods have been limited to better characterize this phenomenon. So far, studies have focused on well-characterized mutations mainly identified in the receptor tyrosine kinase receptor (RTK) signaling pathway. These have been associated with rare disorders in fibroblast growth factor receptors (FGFR) such as achondroplasia and Apert syndrome, which were shown to be related to the selfish expansion in the male germline. The discovery of prospective selfish germline mutations is difficult, in particular, sequencing methods have lacked the accuracy or the sequencing depth to reliably identify and call mutations at such low frequency. The establishment of duplex sequencing opened exciting new possibilities in ultra-rare variant detection with a very high accuracy for a sequencing-based method. This is the first study that has used this sequencing approach to explore this type of mutagenesis directly in sperm in the FGFR3 gene. With our unique approach, we found mutations associated with congenital disorders at increased frequencies in sperm of older donors, but we also identified new unreported selfish mutations expanding with age. We further characterized some of these identified mutations in a larger cohort of sperm donors and in a dissected testis with droplet digital PCR and our in-house bead-amplification method. Finally, we analyzed the change in receptor signaling using a microscopic-based approach known as micropatterning that surpasses in simplicity and accuracy the golden stranded Western blotting. Our work showcases new and accurate approaches for the study of de novo mutations in the human male germline and sheds light into different mutational mechanisms potentially affecting the receptor kinase activity and the potential risk of older individuals fathering an affected child with a rare disorder

Period	24 Sept 2021
Event title	Österreichische Gesellschaft fuer Humangenetik
Event type	Conference
Location	AustriaShow on map