Familial isolated acanthosis nigricans as a result of a recurrent FGFR3 truncating mutation

Abstract

Few cases of isolated (nonsyndromic, nonendocrinopathy) familial acanthosis nigricans (FAN) have been described, and most have not included genetic testing. We present a three-generation family with isolated FAN, whose genetic study revealed a heterozygous FGFR3 gene variant [NM_0001425: c.2302G>T; p.(Glu768Ter); E768X]. We propose genetic mechanisms that could explain the pro-mitogenic effect on the skin without bone involvement and the spectrum of clinical manifestations associated with germline FGFR3 mutations.