PMC7509567_01
(a) Intraoral initial situation. (b) Intraoral situation after root planning and gingivectomy. (c) At 6 months, end of the first phase of periodontal treatment.
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fig1
The endobuccal clinical examination (Figure 1(a)) revealed the presence of a bimaxillary multiring orthodontic appliance and major, generalized gingival inflammation with spontaneous bleeding.
Identification of a mosaic PIK3CA missense mutation in a gingival biopsy. (a) Next-generation sequencing (NGS) of the gingival biopsy sample identified a missense mutation in exon 6 of the PIK3CA gene, as indicated by the yellow square. Twenty-two percent of reads showed the G>A change (324/1475 reads, 174+ 150-), suggesting a potential mosaic mutation. (b) Direct Sanger sequencing of 3 independent samples from the patient confirmed the presence of the missense mutation in the (i) gingival biopsy sample and showed the absence of this mutation in the (ii) blood and (iii) saliva samples, supporting the hypothesis of a mosaic mutation.
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fig2
The pathogenic mutation NM_006218.2:c1093G>A (p.Glu365Lys) was found only in the gingival biopsy with an allelic ratio of 22% (Figure 2).
PMC7509567_02
(a) Intraoral situation for patient 2. (b) Aspect of the inflammatory papillae between teeth 42 and 43. (c) Result of the genetic analysis.
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fig3
The medical history revealed a cerebral surgery in 2013. The clinical oral examination revealed a gingival inflammation, with induced bleeding and the same erythematous appearance of certain papillae (Figure 3(a)). Gingival biopsy was performed on the distal papilla of tooth 42 (Figure 3(b)), and a saliva sample was taken. On the gingival sample, a rare missense mutation was found (Figure 3(c)): NM_006218.2c.1635G>T p.E545D (p.Glu545Asp).