Juvenile Paget's disease (JPD), an autosomal recessive osteopathy, features rapidly remodeling woven bone, osteopenia, fractures, and progressive skeletal deformity that can be fatal by young adult life. Homozygous deletion of the TNFRSF11B gene, encoding osteoprotegerin (OPG), was identified as the cause of JPD in two Navajo families. Previously, a defect in the RANK (receptor activator of nuclear factor ?-B) gene was determined to be the cause of a related disorder, familial expansile osteolysis (FEO). Hence, mutations in genes involved in the OPG/RANKL/RANK/NF-?B signaling pathway are responsible for JPD and related disorders of bone turnover. The long-range goal of this study is to identify other mutations in members of the OPG/RANKL/RANK/NF-?B pathway that cause JPD and related diseases in newly-ascertained patients, and to use in vitro cell modeling systems to assess the downstream effects of these mutations, to elucidate the pathobiology of these disorders.
The Specific Aims of this project are:
Specific Aim 1 : Ascertain and evaluate additional patients worldwide with juvenile Paget's disease (JPD), familial expansile osteolysis (FEO), and related disorders.
Specific Aim 2 : In new patients with JPD, FEO, and related disorders, identify the genetic defects that cause these skeletal diseases.
Specific Aim 3 : Characterize the downstream effects of mutant OPG, RANK, and other members of the OPG/RANKL/RANK/NF-?B signaling pathway on osteoclast formation and action. Additional patients will be ascertained, and evaluated radiographically, biochemically, and molecularly. DNA and RNA samples will be screened for mutations in TNFRSF11B, encoding OPG, TNFRSF11A, encoding RANK, and TNFSF11, encoding RANKL, using PCR and capillary DNA sequencing, and RT-PCR. We will also use a microarray-based copy number analysis to identify potential genomic defects in these patients, and identify new candidate genes. For patients without mutations in the OPG, RANK, or RANKL genes, large-scale Solexa sequencing will be used to search other candidate genes in the OPG/RANKL/RANK/NF-?B signaling pathway for disease-causing mutations, including SQSTM1, VCP, TRAF6, aPKC, NIK, and others. Modulators of RANK signaling will also be examined, including TRAIL, IL-1, MCSF, c-FMS and additional cytokines and their cognate receptors. In vitro osteoclast culture assays will be used to determine downstream effects of mutations on osteoclast formation and function. These studies will further elucidate the genetic bases for JPD, FEO, and related disorders of bone turnover, caused by defects in the OPG/RANKL/RANK/NF-?B signaling pathway, which is critical for osteoclast formation and action.
This project combines clinical evaluation, genetic analysis, and experimental studies for patients and their families with rare bone diseases, including juvenile Paget's disease, familial expansile osteolysis, and related disorders. By understanding the genetic causes and cellular mechanisms of these skeletal diseases, new and better treatments can be developed. The information gained from this study may also be useful for therapy in common bone diseases, such as osteoporosis.
|Frederiksen, Anja L; Larsen, Martin J; Brusgaard, Klaus et al. (2016) Neonatal High Bone Mass With First Mutation of the NF-ÎºB Complex: Heterozygous De Novo Missense (p.Asp512Ser) RELA (Rela/p65). J Bone Miner Res 31:163-72|
|Phatarakijnirund, Voraluck; Mumm, Steven; McAlister, William H et al. (2016) Congenital insensitivity to pain: Fracturing without apparent skeletal pathobiology caused by an autosomal dominant, second mutation in SCN11A encoding voltage-gated sodium channel 1.9. Bone 84:289-98|
|GuaÃ±abens, NÃºria; Mumm, Steven; Gifre, Laia et al. (2016) Idiopathic Acquired Osteosclerosis in a Middle-Aged Woman With Systemic Lupus Erythematosus. J Bone Miner Res 31:1774-82|
|Gottesman, Gary S; Madson, Katherine L; McAlister, William H et al. (2016) Auricular ossification: A newly recognized feature of osteoprotegerin-deficiency juvenile Paget disease. Am J Med Genet A 170A:978-85|
|Mumm, Steven; Huskey, Margaret; Duan, Shenghui et al. (2014) Multicentric carpotarsal osteolysis syndrome is caused by only a few domain-specific mutations in MAFB, a negative regulator of RANKL-induced osteoclastogenesis. Am J Med Genet A 164A:2287-93|
|Whyte, Michael P; Tau, Cristina; McAlister, William H et al. (2014) Juvenile Paget's disease with heterozygous duplication within TNFRSF11A encoding RANK. Bone 68:153-61|
|Whyte, Michael P; Madson, Katherine L; Mumm, Steven et al. (2014) Rapid skeletal turnover in a radiographic mimic of osteopetrosis. J Bone Miner Res 29:2601-9|
|Schafer, Anne L; Mumm, Steven; El-Sayed, Ivan et al. (2014) Panostotic expansile bone disease with massive jaw tumor formation and a novel mutation in the signal peptide of RANK. J Bone Miner Res 29:911-21|
|Saki, Forough; Karamizadeh, Zohreh; Nasirabadi, Shiva et al. (2013) Juvenile paget's disease in an Iranian kindred with vitamin D deficiency and novel homozygous TNFRSF11B mutation. J Bone Miner Res 28:1501-8|
|Campeau, Philippe M; Lu, James T; Sule, Gautam et al. (2012) Whole-exome sequencing identifies mutations in the nucleoside transporter gene SLC29A3 in dysosteosclerosis, a form of osteopetrosis. Hum Mol Genet 21:4904-9|
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