Mutations in pregnancy-associated plasma protein A2 cause short stature due to low IGF-I availability
Mutations in multiple genes of the growth hormone/IGF-I axis have been identified in syndromes marked by growth failure. However, no pathogenic human mutations have been reported in the six high-affinity IGF-binding proteins (IGFBPs) or their regulators, such as the met alloproteinase pregnancy-asso...
| Autores: | ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; |
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| Tipo de documento: | Artículo |
| Fecha de publicación: | 2016 |
| País: | España |
| Institución: | Universidad Autónoma de Madrid |
| Repositorio: | Biblos-e Archivo. Repositorio Institucional de la UAM |
| Lenguaje: | Inglés |
| OAI Identifier: | oai:repositorio.uam.es:10486/677926 |
| Acceso en línea: | http://hdl.handle.net/10486/677926 https://dx.doi.org/10.15252/emmm.201506106 |
| Nivel de acceso: | Acceso abierto |
| Palabra clave: | Bone Delayed growth Growth hormone IGF bioavailability IGF-binding proteins Medicina |
| Sumario: | Mutations in multiple genes of the growth hormone/IGF-I axis have been identified in syndromes marked by growth failure. However, no pathogenic human mutations have been reported in the six high-affinity IGF-binding proteins (IGFBPs) or their regulators, such as the met alloproteinase pregnancy-associated plasma protein A2 (PAPP-A2) that is hypothesized to increase IGF-I bioactivity by specific proteolytic cleavage of IGFBP-3 and -5. Multiple members of two unrelated families presented with progressive growth failure, moderate microcephaly, thin long bones, mildly decreased bone density and elevated circulating total IGF-I, IGFBP-3, and -5, acid labile subunit, and IGF-II concentrations. Two different homozygous mutations in PAPPA2, p.D643fs25* and p.Ala1033Val, were associated with this novel syndrome of growth failure. In vitro analysis of IGFBP cleavage demonstrated that both mutations cause a complete absence of PAPP-A2 proteolytic activity. Size-exclusion chromatography showed a significant increase in IGF-I bound in its ternary complex. Free IGF-I concentrations were decreased. These patients provide important insights into the regulation of longitudinal growth in humans, documenting the critical role of PAPP-A2 in releasing IGF-I from its BPs. |
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