Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.12.2 (MEK)
 18,161 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

RASopathies are a clinically heterogeneous group of conditions caused by mutations in 1 of 16 proteins in the RAS-mitogen activated protein kinase (RAS-MAPK) pathway. Recently, mutations in RIT1 were identified as a novel cause for Noonan syndrome. Here we provide additional functional evidence for a causal role of RIT1 mutations and expand the associated phenotypic spectrum. We identified two de novo missense variants p.Met90Ile and p.Ala57Gly. Both variants resulted in increased MEK-ERK signaling compared to wild-type, underscoring gain-of-function as the primary functional mechanism. Introduction of p.Met90Ile and p.Ala57Gly into zebrafish embryos reproduced not only aspects of the human phenotype but also revealed abnormalities of eye development, emphasizing the importance of RIT1 for spatial and temporal organization of the growing organism. In addition, we observed severe lymphedema of the lower extremity and genitalia in one patient. We provide additional evidence for a causal relationship between pathogenic mutations in RIT1, increased RAS-MAPK/MEK-ERK signaling and the clinical phenotype. The mutant RIT1 protein may possess reduced GTPase activity or a diminished ability to interact with cellular GTPase activating proteins; however the precise mechanism remains unknown. The phenotypic spectrum is likely to expand and includes lymphedema of the lower extremities in addition to nuchal hygroma.
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PMID:Mutations in RIT1 cause Noonan syndrome - additional functional evidence and expanding the clinical phenotype. 2595 49

Cardio-facio-cutaneous (CFC) syndrome is a very rare and sporadic disease whose characteristics include dysmorphic facial appearance, ectodermal abnormalities, cardiac abnormalities, growth retardation and neurodevelopmental delay. This syndrome is classified as one of the RAS syndromes which are caused by altered signal transduction of the RAS/MAPK (mitogen activated protein kinase) pathway due to the mutation of genes including BRAF, MEK1/2, HRAS and KRAS. Other RAS syndromes, such as Costello syndrome and Noonan syndrome, share clinical features with CFC. Moreover, patients with the same clinical phenotype may have different molecular diagnoses. Clinical diagnosis is the starting pointfor correct classification. We describe the clinical data of one case of CFC syndrome, genetically determined by KRAS mutation, that involved chylothorax, lymphedema, sinus pericranii, craniosynostosis, and seizures. This is the second case report of the literature.
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PMID:LYMPHODYSPLASIA AND KRAS MUTATION: A CASE REPORT AND LITERATURE REVIEW. 2693 59