Hyposalivation in a 16-year-old girl: a case of salivary gland aplasia

Aplasia of the Major and Minor Salivary Glands: Report of a Rare Case

Background

Aplasia of the salivary glands, either partial or involving all the major and possibly the minor salivary glands, is a very rare cause of hyposalivation. The aim of this case report is to present a case of aplasia of the major and minor salivary glands and discuss the relevant literature.

Methods

A 23-year-old woman, with a non-contributory medical and family history was referred due to rampant caries, that could not be attributed to any obvious aetiology. No sicca symptoms, previous parotid gland swelling or general symptoms were reported. Clinically, oral mucosa dryness and extended dental erosions and caries were observed, while the orifices of the excretory ducts of the parotid and submandibular salivary glands were not evident. Unstimulated and stimulated saliva flow rates were severely diminished, while a diagnostic biopsy of the lower lip revealed absence of minor salivary glands. Detailed hematologic and immunological investigations to exclude systemic disorders were also within normal limits. Ultrasound and magnetic resonance imaging revealed the absence of all major salivary glands, confirming the clinical diagnosis of congenital aplasia of the salivary glands.

Results

Oral hygiene instructions and dietary advice were given while dental products with fluoride and saliva substitutes were administered and appropriate dental treatment was implemented. Regular dental follow-up was also advised.

Conclusions

Timely diagnosis of aplasia of the salivary glands is important, considering the detrimental effects of the absence of saliva on oral health. Management consists of the use of saliva substitutes, nutritional adaptation, maintenance of oral health and regular dental follow-ups.

Sox9 function in salivary gland development

BACKGROUND

Organogenesis is regulated by morphogen signaling and transcription networks. These networks differ between organs, and identifying the organ-specific network is important to clarify the molecular mechanisms of development and regeneration of organs. Several studies have been conducted to identify salivary gland-specific networks using a mouse submandibular gland model. The submandibular glands (SMGs) of mice manifest as a thickening of the oral epithelium at embryonic day 11.5 and invaginate into the underlying mesenchyme. The network between Fgf10 and Sox9 is involved in SMG development in mice.

HIGHLIGHT

Sox9, a member of the Sox family, is expressed in the SMG in mice from the embryonic stage to the adult stage, although the distribution changes during development. A null mutation of mouse Sox9 is lethal during the neonatal period due to respiratory failure, whereas deletion of Sox9 in the oral epithelium using the Cre/lox P system, can lead to smaller initial buds of SMGs in conditional knockout (cKO) mice than in normal mice. In addition, we showed that adenoviral transduction of Sox9 and Foxc1 genes into mouse embryonic stem cell-derived oral ectoderm could induce salivary gland rudiment in an organoid culture system. ChIP-sequencing revealed that Sox9 possibly regulates several tube- and branching-formation-related genes.

CONCLUSION

Sox9 may serve as an essential transcription factor for salivary gland development. The Sox9-mediated pathway can be a promising candidate for regenerating damaged salivary glands.

Aplasia of the lacrimal and major salivary glands (ALSG). First case report in spanish population and review of the literature

Aplasia of the lacrimal and the major salivary glands (ALSG) is a rare disorder with scarce cases described in the recent literature. The pattern of genetic inheritance is autosomal dominant with variable expressivity. A 40 years male patient was referred to the Oral and Maxillofacial Service at the Hospital Universitario de A Coruña diagnosed with complete agenesis of all salivary glands. Our case it is the first of ALSG syndrome in the Spanish literature. Imaging tests are necessary to confirm the lack of formation of salivary glands and alteration of lacrimal system. A mutation of FGF10 has been proposed as the responsible of the syndrome. The management of the lacrimal alteration depends of the clinical findings. Clinical suspicion remains the principal tool to diagnose the syndrome.

Key words:ALSG, salivary glands aplasia.