A standardized approach to test missense PNPLA1 rare genetic variants of uncertain significance in epidermal differentiation disorders

Congenital ichthyoses, now renamed epidermal differentiation disorders (EDDs) (syndromic EDD or nonsyndromic EDD), are rare, disabling conditions caused by sequence variations in epidermal barrier genes. However, 5-10% of variants, called "variants of uncertain significance" (VUS), remain uncharacterized, and their pathogenicity is not demonstrated. We developed an approach for classifying VUS in nonsyndromic EDD associated with variant in <i>PNPLA1</i>. We generated <i>PNPLA1</i>-knockout human keratinocytes. PNPLA1, encoded by a missense VUS or by the reference coding sequence, was expressed after lentiviral transduction in the <i>PNPLA1</i>-knockout cells. Transduced cells were used to produce human epidermal equivalents, and the functionality of the normal or VUS-encoded proteins was evaluated. Compared with <i>PNPLA1</i>-knockout human epidermal equivalents re-expressing normal PNPLA1, <i>PNPLA1</i>-knockout human epidermal equivalents showed disrupted synthesis of ω-O-acylceramide, the normal product of PNPLA1, as well as abnormal vesicle-like structures and immature cornified envelopes, characteristic of the epidermis of patients with <i>PNPLA1</i> variants. Human epidermal equivalents expressing the <i>PNPLA1</i> VUS showed similar abnormalities, consistent with an impaired PNPLA1 function. This work demonstrated a feasible strategy to help reclassifying missense VUS, which can be extended to other EDD-related genes. Although further efforts are needed to translate this approach into clinical practice and help overcome current diagnostic limitations, such models are valuable tools for pathophysiological and preclinical research on EDDs.

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Journal
JID Innovations
Published
2025-12-13
DOI
https://doi.org/10.1016/j.xjidi.2025.100442
Primary Topic
Skin and Cellular Biology Research
Type
article
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0.00

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article

A standardized approach to test missense PNPLA1 rare genetic variants of uncertain significance in epidermal differentiation disorders

Sèverine Garnier, Corinne Leprince, Pauline Le Faouder, Lukáš Opálka et al.
JID Innovations
Skin and Cellular Biology Research
article

A standardized approach to test missense PNPLA1 rare genetic variants of uncertain significance in epidermal differentiation disorders

Sèverine Garnier, Corinne Leprince, Pauline Le Faouder, Lukáš Opálka, Isabelle Fourquaux, N. Pell, Nathalie Jonca, Justine Bertrand‐Michel, Olga López Serrano, Séverine Courrech, J. Mazereeuw‐Hautier, Jairo Mejia, Elaine R. Levy, Aïna Millán‐Sánchez, Pauline Bernard, Catherine Clément, K. Vavrova
article en

Abstract

Congenital ichthyoses, now renamed epidermal differentiation disorders (EDDs) (syndromic EDD or nonsyndromic EDD), are rare, disabling conditions caused by sequence variations in epidermal barrier genes. However, 5-10% of variants, called "variants of uncertain significance" (VUS), remain uncharacterized, and their pathogenicity is not demonstrated. We developed an approach for classifying VUS in nonsyndromic EDD associated with variant in <i>PNPLA1</i>. We generated <i>PNPLA1</i>-knockout human keratinocytes. PNPLA1, encoded by a missense VUS or by the reference coding sequence, was expressed after lentiviral transduction in the <i>PNPLA1</i>-knockout cells. Transduced cells were used to produce human epidermal equivalents, and the functionality of the normal or VUS-encoded proteins was evaluated. Compared with <i>PNPLA1</i>-knockout human epidermal equivalents re-expressing normal PNPLA1, <i>PNPLA1</i>-knockout human epidermal equivalents showed disrupted synthesis of ω-O-acylceramide, the normal product of PNPLA1, as well as abnormal vesicle-like structures and immature cornified envelopes, characteristic of the epidermis of patients with <i>PNPLA1</i> variants. Human epidermal equivalents expressing the <i>PNPLA1</i> VUS showed similar abnormalities, consistent with an impaired PNPLA1 function. This work demonstrated a feasible strategy to help reclassifying missense VUS, which can be extended to other EDD-related genes. Although further efforts are needed to translate this approach into clinical practice and help overcome current diagnostic limitations, such models are valuable tools for pathophysiological and preclinical research on EDDs.

JID InnovationsVol. 6(2)
Centre National de la Recherche Scientifique (FR), Inserm (FR), École Nationale Vétérinaire de Toulouse (FR), Université Fédérale de Toulouse Midi-Pyrénées (FR), Charles University (CZ), Centre Hospitalier Universitaire de Toulouse (FR), Centre de Recherches en Cancérologie de Toulouse (FR), Toulouse Mathematics Institute (FR), Centre de Biologie du Développement (FR), Institute of Advanced Chemistry of Catalonia (ES), Hôpital Purpan (FR), Institut des Maladies Métaboliques et Cardiovasculaires (FR)
EuroNanoMed III, European Commission, Agence Nationale de la Recherche, Institut National de la Santé et de la Recherche Médicale, Ministerio de Ciencia e Innovación, Universitat de Barcelona, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, Instituto de Salud Carlos III
Openalex Percentile: Top 58%
Skin and Cellular Biology Research
DOIOpen Access PDFOpenAlex
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