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

Figure 2

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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