Gingival Biopsy to Detect Mosaicism in Overgrowth Syndromes: Report of Two Cases of Megalencephaly-Capillary Malformation Syndrome with Periodontal Anomalies

Mathieu Marty; Carole Bonnaud; Natalie Jones; Michel Longy; Frédéric Vaysse; Eric Bieth; Isabelle Bailleul-Forestier

doi:10.1155/2020/8826945

Gingival Biopsy to Detect Mosaicism in Overgrowth Syndromes: Report of Two Cases of Megalencephaly-Capillary Malformation Syndrome with Periodontal Anomalies

Case Rep Dent. 2020 Sep 12:2020:8826945. doi: 10.1155/2020/8826945. eCollection 2020.

Authors

Mathieu Marty¹, Carole Bonnaud¹, Natalie Jones², Michel Longy², Frédéric Vaysse¹, Eric Bieth³, Isabelle Bailleul-Forestier^{1

4}

Affiliations

¹ Paul Sabatier Toulouse III University, Department of Paediatric Dentistry, CHU Toulouse, F-31000, France.
² Cancer Genetics Unit & INSERM U1218, Institut Bergonié, Bordeaux University, Bordeaux, France.
³ Paul Sabatier Toulouse III University, Genetics Unit, CHU Toulouse, F-3100, France.
⁴ KU Leuven University, Belgium.

Abstract

Background: Megalencephaly-capillary malformation (MCAP) is a rare overgrowth syndrome caused by postzygotic activating mutations in the PIK3CA gene.

Aim: To illustrate the benefits of gingival biopsy in the genetic diagnosis of overgrowth syndromes.

Design: Gingival biopsy was performed on a 13-year-old patient and a 16-year-old patient with MCAP and who suffered from periodontal disease. PIK3CA sequencing was performed on DNA extracted from gingival biopsies, blood, and saliva.

Results: Pathogenic p.Glu365Lys and p.Glu545Asp PIK3CA mutations were found in the gingival biopsies with an allelic frequency of 22% and 35%, respectively, while they were undetectable in blood or saliva. The genetic diagnosis of MCAP through detection of PIK3CA somatic mosaicism in a periodontal biopsy is unprecedented.

Conclusions: Considering the tissue distribution and level of somatic mosaicism for PIK3CA mutation, the composite embryologic origin of periodontium and its high fibroblast cell content make it an ideal target for molecular analysis in overgrowth syndromes, and multidisciplinary approach including paediatric dentists should be encouraged. In addition, our clinical findings suggest that periodontal disease is part of the MCAP phenotypic spectrum and should be systematically investigated.

Publication types

Case Reports