TNFRSF11A-Associated Dysosteosclerosis: A Report of the Second Case and Characterization of the Phenotypic Spectrum

J Bone Miner Res. 2019 Oct;34(10):1873-1879. doi: 10.1002/jbmr.3805. Epub 2019 Aug 5.

Abstract

Dysosteosclerosis (DOS) is a distinct form of sclerosing bone disease characterized by irregular osteosclerosis and platyspondyly. DOS is genetically heterogeneous; however, only five cases with SLC29A3 mutations and a single case with a splice-site mutation of TNFRSF11A have been reported, and TNFRSF11A is also a causal gene for osteopetrosis, autosomal recessive 7 (OP-AR7). Thus, the causal genes of DOS and their genotype-phenotype associations remain unclear. In this study, we examined a Japanese patient with DOS and found a novel variant in TNFRSF11A. The homozygous variant was a G to T transversion at the first nucleotide of exon 9 (c.784G>T). Although the variant was predicted to cause a stop codon mutation (p.E262*), in silico evaluation of the exonic splicing elements followed by RT-PCR for the patient-derived cells showed that it caused aberrant splicing due to the change in the exonic splicing element and produced two types of aberrant transcripts: One caused a premature stop codon (p.E262Vfs*17) leading to nonsense mutation-mediated mRNA decay; the other produced a protein with interstitial deletion (p.E262_Q279del). The effects of the mutation on five splicing isoforms of TNFRSF11A were different from those in OP-AR7, but comparable with those in the first DOS with the TNFRSF11A mutation. Thus, we identified the second case of DOS caused by the TNFRSF11A splice-site mutation and confirmed the novel disease entity. © 2019 American Society for Bone and Mineral Research.

Keywords: ALTERNATIVE SPLICING; MUTATION; NONSENSE MUTATION-MEDIATED mRNA DECAY; OSTEOPETROSIS; RANK.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Asian Continental Ancestry Group
  • Codon, Terminator*
  • Exons*
  • Humans
  • Japan
  • Male
  • Middle Aged
  • Osteosclerosis / genetics*
  • Point Mutation*
  • Receptor Activator of Nuclear Factor-kappa B / genetics*

Substances

  • Codon, Terminator
  • Receptor Activator of Nuclear Factor-kappa B
  • TNFRSF11A protein, human

Supplementary concepts

  • Dysosteosclerosis