A Missense Mutation (c.1037 G > C, p. R346P) in PAPSS2 Gene Results in Autosomal Recessive form of Brachyolmia Type 1 (Hobaek Form) in A Consanguineous Family

Background: Brachyolmia is a skeletal disorder with an autosomal mode of inheritance (both dominant and recessive) in which the patients have a short height, scoliosis and a reduced trunk size. Methods: From the Muzaffargarh District in Pakistan, a consanguineous family with multiple Brachyolmia-affected subjects were enrolled in the present study. Basic epidemiological data and radiographs were collected for the subjects. Whole exome sequencing (WES) which was followed by Sanger sequencing was applied to report the geneticbasic of Brachyolmia. Results: The WES identified a missense mutation (c.1037 G > C, p. R346P) in exon 9 of the PAPSS2 gene that was confirmed by the Sanger sequencing in the enrolled subjects. The mutation followed a Mendalian pattern with an autosomal recessive inheritance mode. Multiple sequence alignment by Clustal Omega indicated that the PAPSS2 mutation-containing domain is highly conserved. The HEK293T whole-cell extract that was transfected with the Myc-tagged PCMV6-PAPSS2 of both the wild and mutant constructs were resolved by SDS-PAGE as well as by a Western blot, which confirmed that there are different PAPSS2 protein expression patterns when they were compared between the control and Brachyolmia patients. This difference between the normal and mutated protein was not evident when the three-dimensional computational structures were generated using homology modeling. Conclusion: We report a missense mutation (c.1037 G > C, p. R346P) in the PAPSS2 gene that caused Brachyolmia in a consanguineous Pakistani family.