Cutis verticis gyrata and Noonan syndrome: report of two cases with pathogenetic variant in SOS1 gene

Background Noonan and Noonan-like syndromes are multisystem genetic disorders, mainly with autosomal dominant trasmission, caused by mutations in several genes. Missense pathogenetic variants of SOS1 gene are the second most common cause of Noonan syndrome (NS) and account approximately for 13% to 17% of cases. Subjects carrying a pathogenetic variant in SOS1 gene tend to exhibit a distinctive phenotype that is characterized by ectodermal abnormalities. Cutis verticis gyrata (CVG) is a rare disease, congenital or acquired, characterized by the redundancy of skin on scalp, forming thick skin folds and grooves of similar aspect to cerebral cortex gyri. Several references in the literature have reported association between nonessential primary form of CVG and NS. Case presentation we report two cases of newborns with CVG and phenotype suggestive for NS who have been diagnosed to harbour the same pathogenetic variant in SOS1 gene. Conclusions previously described patients with NS presenting CVG had received only clinical diagnosis. Therefore we report the first patients with CVG in which the clinical suspicion of NS is confirmed by molecolar analysis.