Analysis of mutations in the PIK3CA and FGFR3 genes in verrucous epidermal nevus

Abstract

Verrucous epidermal nevi are congenital hamartomas composed of keratinocytes and may occur alone or in association with developmental abnormalities. A close relationship between variations in the PIK3CA and FGFR3 genes and the appearance of nevi has been recently reported. Based on that, we performed molecular assays for the identification of E542K, E545G/K and H1047R mutations in the PIK3CA gene and of the R248C mutation in the FGFR3 gene. Interestingly, during the amplification process, we did not observe the PCR product of exon 9 of the PIK3CA gene, a region comprising amino acids 542-545. This strongly suggests the occurrence of a microdeletion of that region and indicates a possible allelic variant, which has not yet being described in the literature.

Seborrheic keratosis arising on an epidermal nevus with HRAS p.G13R mutation

“…However, in rare cases, skin tumors, such as squamous cell carcinomas, basal cell carcinomas, and poroid cell neoplasms, can arise within the lesion . To date, several somatic gene mutations, such as FGFR3 , PIK3CA , and HRAS , have been identified in EN . Herein, we describe a case of seborrheic keratosis (SK) arising on an area affected by EN with the HRAS p.G13R mutation that was identified by next‐generation sequencing (NGS).…”

Linear verrucous epidermal nevus with oral manifestations: report of two cases

“…The prevalence of epidermal nevi is 0.1 to 0.5% and there is no predilection for gender or race [2]. The incidence of all types of epidermal nevi is estimated to be one in 1000 live births.…”

“…Epidermal nevi (EN) are hamartomas characterized by hyperplasia of any part of the epidermis, including adnexal structures. Linear verrucous epidermal nevus (LVEN) originates from keratinocyte hyperplasia, and they are clinically characterized by skin-colored or brown papules and/or plaques, with a verrucous surface, appearing linearly, following the lines of Blaschko [1,2]. Although the etiology is not completely understood, it seems that this is a mosaic disorder resulting from a postzygotic mutation [3,4].…”

Keratinocytic epidermal nevus with ipsilateral breast hypoplasia

“…Another possible explanation for this patient’s unique presentation is a common mosaic genetic mutation. KENs have been shown to be associated with somatic mutations in FGFR3 , PIK3CA , and HRAS , all of which are involved in cellular signaling and growth regulation (Miranda et al, 2013). Activating mutations in these genes are more commonly associated with tissue hyperplasia (including CLOVE syndrome, macrocephaly-capillary malformation syndrome, and KENs).…”