Endosteal Hyperostosis Associated With Biallelic Variants in POLR3GL
Biallelic variants in POLR3A, POLR3B, POLR1C, and POLR3K encoding Pol III subunits have been observed in individuals with neurodevelopmental disorders; however, a new report has identified biallelic variants in POLR3GL, a gene encoding a Pol III subunit, to also be associated with disease. Using whole exome sequencing in a monozygotic twin and an unrelated individual, the investigators detected homozygous and compound heterozygous POLR3GL splice acceptor site variants. RNA sequencing confirmed the loss of full-length POLR3GL RNA transcripts in blood samples, and the phenotypes were mainly characterized by axial endosteal hyperostosis, oligodontia, short stature, and mild facial dysmorphisms. These findings further expand the spectrum of POLR3-related disorders and suggest POLR3GL should be included in genetic testing if certain neurodevelopmental disorders are suspected.
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Terhal PA, Vlaar JM, Middelkamp S, et al. Biallelic variants in POLR3GL cause endosteal hyperostosis and oligodontia. Eur J Hum Genet. 2019 May 14. doi: 10.1038/s41431-019-0427-0.
Photo Credit: Al Kaissi A, et al. Distinctive spinal changes in two patients with unusual forms of autosomal dominant endosteal hyperostosis: a case series. J Med Case Reports. 2008;1:142. doi:10.1186/1752-1947-1-142.