Role of 5’ UTR MYH3 Variant in Distal Arthrogryposis Kim T. Ha1, Colby T. Marvin2, Kati J. Buckingham2, Kathryn M. Shively2, Jessica X. Chong2, Michael J. Bamshad2,3,4 1UW GenOM Project, 2Department of Pediatrics, 3Department of Genome Sciences, University of Washington, Seattle, WA, 4Seattle Children’s Hospital, Seattle, WA Abstract Methods Distal Arthrogryposis (DA) syndromes are a group of disorders with 1 2 3 4 5 a wide breadth of phenotypic severity. A study by Cameron‐Christie et al. (2018) found that individuals with recessive Spondylo‐ carpotarsal Synostosis Syndrome were compound heterozygous for a coding MYH3 variant and c.‐9+1G>A (rs557849165). We are Credit: Thermo Fisher Scientific Credit: Bio‐Rad Laboratories Credit: Thermo Fisher Scientific Credit: Thermo Fisher Scientific Credit: Informer Technologies, Inc interested in discovering if individuals with DA and MYH3 variants Primers were used to Gel electrophoresis Big Dye Terminator was Electropherograms were Electropherograms were amplify 5’ UTR region of confirmed successful used for DNA sequencing created using an ABI 3130 aligned and examined were carriers for the variant c.‐9+1G>A, as a means to explain more MYH3 with Polymerase amplification of the reactions xl Sanger Sequencer using CodonCode Aligner Chain Reaction (PCR) from desired region severe phenotypes seen. We screened a cohort of individuals with genomic DNA DA and MYH3 variants in the previously unscreened non‐coding region of exon 2. We did not detect the variant in any individuals Results Discussion and Future Direction screened. Further investigation will be conducted on additional DA candidates to better identify the genotype‐phenotype relationship MYH3 • of various forms within DA1, DA2A, and DA2B. No evidence to suggest this variant affects phenotypic severity within these forms of DA as it was not found in any individuals screened Background • The Bamshad lab will continue screening patients Figure 2. Gene diagram of MYH3 (NM_002470.3). Note, only the non‐coding region of with DA for the rs557849165 variant and exon 2 was sequenced. • Distal Arthrogryposis (DA) is characterized by multiple investigate other candidate genes to identify other congenital limb contractures and subdivided into groups based secondary variants that may explain varying levels on additional secondary features of phenotypic severity within each form of DA - DA1: Limb contractures, e.g., overlapping fingers and clubfoot Individual with DA1 Individual with DA2A - DA2B: Overlaps with DA1 with exception of existing non‐ Acknowledgements limb contractures, e.g., triangular face - DA2A: Classical facial features include pursed or pinched Two individuals are affected by I would like to thank the Bamshad laboratory for kindly allowing me to be a part of their lab and research. Thank you to Dr. Michael Bamshad lips in addition to limb contractures for providing me with the opportunity to work on this project and • High degree of phenotypic variability exists within each type Multiple Pterygium and one thank you to Kathryn Shively for her mentorship. Thank you to Lisa, Individual with DA2B Control Sample Greg, and every individual who made the ALVA program possible. I • Mutations in skeletal muscle gene, Myosin Heavy Chain 3 Figure 3. Electropherograms of exon 2 of MYH3 for each type of DA screened within our would also like to acknowledge the UW Office of Research and the (MYH3), are known to cause DA types 1, 2A, and 2B individual is affected by an cohort. Note, blue line indicates location of c.‐9+1G>A. University of Washington GenOM Project (NIH 5R25HG007153‐06). • All individuals screened in this cohort have an existing mutation in MYH3 determined from previous screening, but the unnamed form of DA.Table 1. Composition of Individuals Screened Diagnosis of Individual No. of Individuals References untranslated 5’ region was not screened previously DA2A 29 DA2B 13 Beck, A. E., McMillin, M. J., Gildersleeve, H. I., Kezele, P. R., Shively, K. DA1 3 M., Carey, J. C., ... & Bamshad, M. J. (2013). Spectrum of mutations Multiple Pterygium 2 that cause distal arthrogryposis types 1 and 2B. American Journal of Medical Genetics Part A, 161(3), 550‐555. Sporadic Unknown DA 1 Beck, A. E., McMillin, M. J., Gildersleeve, H. I., Shively, K. M., Tang, A., Total 48 & Bamshad, M. J. (2014). Genotype‐phenotype relationships in Freeman–Sheldon syndrome. American Journal of Medical Genetics • The c.‐9+1G>A variant was not identified in any individual screened Part A, 164(11), 2808‐2813. • Electropherograms reveal 44 individuals have the homozygous wildtype Cameron‐Christie, S. R., Wells, C. F., Simon, M., Wessels, M., Tang, C. genotype at c.‐9+1G>A Z., Wei, W., ... & Cordier, M. P. (2018). Recessive Spondylocarpotarsal Figure 1. Individuals with DA2A demonstrating the range in phenotypic severity Synostosis Syndrome due to compound heterozygosity for variants in within the same diagnosis. Photo credit: Beck, 2014 • 4 individuals did not produce electropherograms MYH3. The American Journal of Human Genetics, 102(6), 1115‐1125. University of Washington GenOM ALVA Project 2018.