Aims: To report the periodontal condition of two siblings (ages 2 and 4) diagnosed with congenital Amegakaryocytic Purpura (AP), who underwent allogeneic hematopoietic stem cell transplant (HSCT) and developed graft-versus-host disease (GVHD) with oral manifestations.

Methods: Clinical history was obtained through physical examination and medical records. Patients received clinical and microbiological assessment at 2 months post-HSCT, when they started to show signs and symptoms of GVHD and were monitored at 8/15-months post-transplant. They were treated by means of prophylaxis and oral hygiene instruction. Two supragingival biofilm samples were collected from each patient and analyzed by Checkerboard DNA-DNA hybridization.

Results: Patients developed severe periodontal clinical attachment loss (CAL) in deciduous dentition associated with recession of the periodontal tissues. They also presented GVHD lesions in the oral mucosa, lips and tongue. Caries lesions, gingivitis, and heavy biofilm deposits were identified. The microbiological profile of biofilm samples presented high levels and proportions of periodontal pathogens, such as Aggregatibacter actinomycetemcomitans.

Conclusion: The cases presented suggested that severe periodontal CAL in children with AP may be an atypical manifestation associated with AP and/or GVHD, which may be aggravated by the presence of a dysbiotic biofilm containing periodontal pathogens, especially A. actinomycetemcomitans.

Keywords: Hematologic Diseases; Periodontal Diseases; Stem CellTransplantation.