Identification of a novel splicing mutation and genotype-phenotype correlations in rare PLS3-related osteoporosis

Abstract Background X-linked early-onset osteoporosis, caused by mutations in plastin3 (PLS3), is an extremely rare disease characterized by low bone mineral density (BMD) and recurrent osteoporotic fractures. There is limited information on genetic and phenotypic spectrum, as well as genotype-phenotype correlations of the disease. Moreover, whether decreased PLS3 levels were also involved in osteoporosis among subjects without PLS3 pathogenic mutations remains unknown. Results We identified a novel splicing mutation (c.892-2A>G) which led to the skipping of exon 9 in a family with X-linked early-onset osteoporosis. Scoliosis represents a new phenotype in the patients harboring PLS3 mutations, which may be corrected by brace treatment. Genotype-phenotype analysis reveals that there was no significant difference in BMD z-scores between different types of reported mutations including this study (p = 0.5). There is a marginally significant negative correlation between age and BMD z-score (p = 0.059, r = - 0.30). The conditions of osteoporosis in all patients were improved after bisphosphonates therapy, with mean BMD z-score increased from -2.9 to -0.57 (p < 0.0001). Serum PLS3 levels in adolescents and adults without PLS3 pathogenic mutations but representing osteoporosis were also evaluated, while no association was found between bone mineral density and PLS3 levels (p > 0.05). Conclusions Our findings expanded the mutation and phenotype spectrum of the rare disease and highlights the importance of early diagnosis and early treatment with bisphosphonates. More reports of cases with PLS3 mutation and function studies of the gene are warranted to understand genotype-phenotype correlations.