Other less common lesions in HRAS can induce a milder phenotype on the one hand and a more severe phenotype on the other broadening the spectrum of clinical manifestations in CS-affected individuals.
We report on a premature male with Costello syndrome due to a rare G13CHRAS mutation and describe his clinical features and evolution during the first year of life.
Duplication of Glu37 in the switch I region of HRAS impairs effector/GAP binding and underlies Costello syndrome by promoting enhanced growth factor-dependent MAPK and AKT activation.
We report a patient with typical Costello syndrome and a novel heterozygous missense mutation in codon 117 (c.350A>G, p.Lys117Arg) of the HRAS gene, resulting in constitutive activation of the RAS/MAPK pathway similar to the typical p.Gly12Ser and p.Gly12Ala mutations.
Patients with the HRAS mutation c.173C>T (p.T58I) might go undiagnosed because of the milder phenotype compared with other mutations causing Costello syndrome.
However, some patients carrying HRAS mutations may exhibit prominent congenital muscular dysfunction, although features of CS may be less obvious, suggesting that germline HRAS mutations may underlie some cases of otherwise unclassified neonatal neuromuscular disorders.
Our recent observation that heart tissue from patients with Costello syndrome showed a loss of the glycosaminoglycan chondroitin-4-sulfate (C4S) inspired our present study aimed to explore a functional involvement of the chondroitin sulfate (CS) biosynthesis gene Carbohydrate sulfotransferase 11/Chondroitin-4-sulfotransferase-1 (CHST11/C4ST-1), as well as an impaired chondroitin sulfation balance, as a downstream mediator of oncogenic HRAS in Costello syndrome.
We report here on a female with findings suggestive of CS in whom mutation analysis performed with standard techniques on white blood cell derived DNA did not show an HRAS mutation.
These "giant" spindles were not associated with any evidence of structural damage of the cortex or the thalami and should be considered as phenotypic feature of sleep EEG activity in Costello syndrome because of HRAS mutation.
Here, we report on a novel heterozygous HRAS germline mutation (c.187_207dup, p.E63_D69dup) in a girl presenting with a phenotype at the milder end of the Costello syndrome spectrum.
Paternal uniparental disomy with segmental loss of heterozygosity of chromosome 11 are hallmark characteristics of syndromic and sporadic embryonal rhabdomyosarcoma.
To examine the mechanisms of energy reprogramming by HRAS activation in vivo, we generated knock-in mice expressing a heterozygous Hras G12S mutation (Hras<sup>G12S/+</sup> mice) as a mouse model of Costello syndrome.
We report a patient with typical Costello syndrome and a novel heterozygous missense mutation in codon 117 (c.350A>G, p.Lys117Arg) of the HRAS gene, resulting in constitutive activation of the RAS/MAPK pathway similar to the typical p.Gly12Ser and p.Gly12Ala mutations.