Pathogenic SGMS2 variants are not a common cause of early-onset osteoporosis among Finnish patients

Primary osteoporosis can be caused by pathogenic variants in multiple genes. Recently, rare heterozygous variants in SGMS2, encoding SGMS2, have been identified to cause early-onset osteoporosis or more severe skeletal dysplasia. The incidence of pathogenic SGMS2 variants and their consequent clinical features, however, remain limited.

This study aimed to identify the prevalence and nature of SGMS2 variants in Finnish patients with genetically undiagnosed idiopathic early-onset osteoporosis. All eleven exons and exon-intron boundaries of SGMS2 were sequenced.

In a cohort of 44 patients (42 females and two males, median age at the time of recruitment 60 years, range 25-76 years), we identified one rare heterozygous missense variant (c.715T>C, p.Phe239Leu) and three intronic variants with unknown functional consequences; no pathogenic or likely pathogenic variants were found.

Our results suggest that pathogenic variants in SGMS2 are not a common cause of early-onset idiopathic osteoporosis in Finnish patients. Further studies in larger cohorts and variable skeletal phenotypes are needed to increase our understanding of the role of SGMS2 in skeletal fragility.