Rasopathies case report: concurrence of two pathogenic variations de novo in NF1 and KRAS genes in a patient

Rasopathies are a group of genetic malformative syndromes including neurofibromatosis 1, Noonan, LEOPARD, Costello, cardio-facio-cutaneous, Legius, and capillary malformation-arteriovenous malformation syndromes.

We present a female newborn that consulted at the emergency department with refusal to eat and sleepiness. A shortened femur, thickened nucal fold and suspect for agenesis of the corpus callosum were observed in prenatal ultrasound. Her phenotype included hypertelorism, antimongoloid obliquity of the palpebral fissure, prominent forehead, long filtrum, thickened nucal fold, separated nipples, widespread thickened skinfolds and café-au-lait spots. She had a systolic murmur due to pulmonary valve stenosis. The NF1 gene testing found the pathogenic variant p.E2586X (c.7756G > T) in exon 53, not described in any international database or scientific publications yet. Also, a mutation in the Kras gene was detected (p.Val14lle), which is associated with mild Noonan phenotype. Both variations were de novo.

Not all genes and mutations have already been discovered, so it's important to document new findings, like our patient's, to enrich and update the international database and broaden all possible knowledge about rasopathies. This is the first case to be described presenting simultaneously two mutations in Kras and NF1 genes, whose possible synergic effect regarding its pathogenicity is unknown, but could be interesting towards therapeutic alternatives.