Multifocal heterotopic ossification in a man with germline variants of LIM Mineralization Protein-1 (LMP-1).
Am J Med Genet A
; 191(8): 2164-2174, 2023 08.
Article
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| MEDLINE
| ID: mdl-37218523
ABSTRACT
A 54-year-old man with a history of unimelic, post-traumatic multifocal heterotopic ossification (HO) and normal genetic analysis of ACVR1 and GNAS had variants of unknown significance (VUS) in PDLIM-7 (PDZ and LIM Domain Protein 7), the gene encoding LMP-1 (LIM Mineralization Protein-1), an intracellular protein involved in the bone morphogenetic protein (BMP) pathway signaling and ossification. In order to determine if the LMP-1 variants were plausibly responsible for the phenotype observed, a series of in vitro experiments were conducted. C2C12 cells were co-transfected with a BMP-responsive reporter as well as the LMP-1 wildtype (wt) construct or the LMP-1T161I or the LMP-1D181G constructs (herein designated as LMP-161 or LMP-181) corresponding to the coding variants detected in the patient. A significantly increased BMP-reporter activity was observed in LMP-161 or LMP-181 transfected cells compared to the wt cells. The LMP-181 variant exhibited BMP-reporter activity with a four-fold increase over the LMP-1 wt protein. Similarly, mouse pre-osteoblastic MC3T3 cells transfected with the patient's LMP-1 variants expressed higher levels of osteoblast markers both at mRNA and protein levels and preferentially mineralized when stimulated with recombinant BMP-2 compared to control cells. Presently, there are no pathogenic variants of LMP-1 known to induce HO in humans. Our findings suggest that the germline variants in LMP-1 detected in our patient are plausibly related to his multifocal HO (LMP1-related multifocal HO). Further observations will be required to firmly establish this gene-disease relationship.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Osificación Heterotópica
/
Miositis Osificante
Límite:
Animals
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Humans
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Middle aged
Idioma:
En
Revista:
Am J Med Genet A
Asunto de la revista:
GENETICA MEDICA
Año:
2023
Tipo del documento:
Article
País de afiliación:
Estados Unidos