Hermansky-Pudlak syndrome type 2: A rare cause of severe periodontitis in adolescents-A case study

Jun Chen; Yifan Yang; Binjie Liu; Xiaoli Xie; Wenjie Li

doi:10.3389/fped.2022.914243

Hermansky-Pudlak syndrome type 2: A rare cause of severe periodontitis in adolescents-A case study

Front Pediatr. 2022 Jul 19:10:914243. doi: 10.3389/fped.2022.914243. eCollection 2022.

Authors

Jun Chen^{1

2}, Yifan Yang¹, Binjie Liu^{1

2}, Xiaoli Xie¹, Wenjie Li^{1

3

4}

Affiliations

¹ Hunan Key Laboratory of Oral Health Research, Hunan 3D Printing Engineering Research Center of Oral Care, Hunan Clinical Research Center of Oral Major Diseases and Oral Health, Xiangya School of Stomatology, Central South University, Changsha, China.
² Department of Periodontics, Xiangya Stomatological Hospital, Central South University, Changsha, China.
³ Deparment of Orthodontics, Xiangya Stomatological Hospital, Central South University, Changsha, China.
⁴ Department of Oral Health Science, School of Dentistry, University of Washington, Seattle, WA, United States.

Abstract

Background and aims: Hermansky-Pudlak syndrome (HPS) is an autosomal recessive disorder characterized by oculocutaneous albinism (OCA) and platelet storage pool deficiency. The HPS-2 subtype is distinguished by neutropenia, and little is known about its periodontal phenotype in adolescents. AP3B1 is the causative gene for HPS-2. A 13-year-old Chinese girl presented to our department suffering from gingival bleeding and tooth mobility. Her dental history was otherwise unremarkable. Suspecting some systemic diseases as the underlying cause, the patient was referred for medical consultation, a series of blood tests, and genetic tests. In this case study, periodontal status and mutation screening of one HPS-2 case are presented.

Methods: Blood analysis including a complete blood count (CBC) and glycated hemoglobin levels were measured. Platelet transmission electron microscopy (PTEM) was performed to observe the dense granules in platelets. Whole-exome sequencing (WES) and Sanger sequencing were performed to confirm the pathogenic variants.

Results: A medical diagnosis of HPS-2 was assigned to the patient. Following the medical diagnosis, a periodontal diagnosis of "periodontitis as a manifestation of systemic disease" was assigned to the patient. We identified novel compound heterozygous variants in AP3B1 (NM_003664.4: exon7: c.763C>T: p.Q255^*) and (NM_003664.4: exon1: c.53_56dup: p.E19Dfs^*21) in this Chinese pedigree with HPS-2.

Conclusion: This case study indicates the importance of periodontitis as a possible indicator of underlying systemic disease. Systemic disease screening is needed when a young patient presents with unusual, severe periodontitis, as the oral condition may be the first of a systemic abnormality. Our work also expands the spectrum of AP3B1 mutations and further provides additional genetic testing information for other HPS-2 patients.

Keywords: Hermansky-Pudlak syndrome type 2 (HPS-2); adaptor protein complex 3 (AP3B1); genetics; juvenile; periodontitis.