# Novel Filaggrin Variants Are Associated with Ichthyosis Vulgaris in Mexicans

## TL;DR

This study identifies new genetic variants in the FLG gene linked to ichthyosis vulgaris in Mexican patients, highlighting the prevalence of a specific mutation.

## Contribution

The study reports novel FLG gene variants associated with ichthyosis vulgaris in the Mexican population.

## Key findings

- The R501* variant was found in 15 out of 18 sporadic IV cases.
- Four new FLG variants (p.Q2123R, p.H2118R, p.D2120E, p.S3970L) were identified.
- Novel homozygous and heterozygous variants were found in family members.

## Abstract

Background/Objective: Ichthyosis vulgaris (IV) is a genodermatosis caused by heterozygous, homozygous, or compound heterozygous variants in the filaggrin (FLG) gene on chromosome 1q21, which also predispose individuals to atopic dermatitis. Its incidence is 1 in 80–250 children. The phenotypic characteristics include palmar hyperlinearity, keratosis pilaris, and a fine scale that is most prominent over the lower abdomen, arms, and legs. Our objective was to study the genetic variants in the FLG gene and their associations in patients with ichthyosis vulgaris. Material and methods: Here, we studied eighteen Mexican sporadic cases and four family members with IV. Steroid sulfatase (STS) enzymatic activity, polymerase chain reaction (PCR), and direct sequencing on the FLG gene were conducted. Results: We found the recurrent heterozygous variant R501* in fifteen sporadic cases, while the other three sporadic cases showed four novel (p.Q2123R, p.H2118R, p.D2120E, p.S3970L) variants and one reported (p.Y2119H) variant; members of family 1 and 2 presented novel homozygous and heterozygous (p.S1482Y, p.P2144S) variants. Conclusions: This study added to the novel pathogenic variants in patients with IV and showed that the stop mutations (p.R501*) in the Mexican population are the most prevalent.