Unexpected High Prevalence of Focal Facial Dermal Dysplasia (FFDD) Type IV Is Linked to a Founder Effect in the Belgian Population

Aude Beyens; Stefanie Van De Voorde; Marta Guerreiro Santano Ramos Da Silva; Sofie De Meulemeester; Koen Devriendt; Marleen Goeteyn; Sandra Janssens; R Frank Kooy; Toon Rosseel; Sofie Symoens; Frederik Jan Hes; Kathelijn Keymolen; Boyan Dimitrov; Bert Callewaert

doi:10.1111/cge.14705

Unexpected High Prevalence of Focal Facial Dermal Dysplasia (FFDD) Type IV Is Linked to a Founder Effect in the Belgian Population

Clin Genet. 2025 May;107(5):579-581. doi: 10.1111/cge.14705. Epub 2025 Jan 19.

Authors

Aude Beyens^{1

2}, Stefanie Van De Voorde³, Marta Guerreiro Santano Ramos Da Silva^{1

2}, Sofie De Meulemeester⁴, Koen Devriendt⁵, Marleen Goeteyn⁶, Sandra Janssens^{1

2}, R Frank Kooy⁷, Toon Rosseel^{1

2}, Sofie Symoens^{1

2}, Frederik Jan Hes³, Kathelijn Keymolen³, Boyan Dimitrov³, Bert Callewaert^{1

2}

Affiliations

¹ Center for Medical Genetics Ghent, Ghent University Hospital, Ghent, Belgium.
² Department of Biomolecular Medicine, Ghent University, Ghent, Belgium.
³ Vrije Universiteit Brussel (VUB), Universitair Ziekenhuis Brussel (UZ Brussel), Clinical Sciences, Research Group Reproduction and Genetics, Center for Medical Genetics, Brussels, Belgium.
⁴ Department of Dermatology, Ghent University Hospital, Ghent, Belgium.
⁵ Center for Human Genetics, University Hospitals Leuven, Leuven, Belgium.
⁶ Department of Dermatology, AZ Sint-Jan Brugge, Bruges, Belgium.
⁷ Department of Medical Genetics, University of Antwerp, Antwerp, Belgium.

PMID: 39828664
DOI: 10.1111/cge.14705

Abstract

Focal facial dermal dysplasia (FFDD) type IV is a rare inherited facial defect caused by biallelic variants in CYP26C1. This study reports two novel Belgian FFDD type IV cases, both homozygous for a recurrent CYP26C1 frameshift variant, with a common 700 kb haplotype, indicating a founder effect.

Keywords: focal facial dermal dysplasia type IV; founder effect; homozygosity mapping.

Publication types

Case Reports

MeSH terms

Belgium / epidemiology
Face / abnormalities
Focal Dermal Hypoplasia* / epidemiology
Focal Dermal Hypoplasia* / genetics
Focal Dermal Hypoplasia* / pathology
Founder Effect*
Frameshift Mutation
Haplotypes
Homozygote
Humans
Pedigree
Prevalence

Grants and funding

Research Foundation - Flanders