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.
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.
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.