Hypophosphatasia as a plausible cause of vitamin B6 associated mouth pain: A case-report

Background: Mouth pain has been associated with abnormal vitamin B6 levels. Hypophosphatasia is a rare genetic disease, which causes imbalances between B6 vitamers. We report the case of a patient with hypophosphatasia and burning mouth pain. Case presentation: A 39-year old Caucasian male with chronic burning mouth pain underwent extensive investigations with no cause of the pain being found. During the course of the investigation, an elevated vitamin B6 (pyridoxal phosphate) level was detected, which led to the diagnosis of hypophosphatasia. We hypothesize that the patient’s mouth pain stems from hypophosphatasia through a B6 dependent mechanism. Conclusions: Mouth pain may, in some cases, be a symptom of hypophosphatasia and when investigating B6 in relation to mouth pain, attention should be paid to the exact B6 vitamer measured. The case underlines the importance of low alkaline phosphatase results, especially in patients with unexplained pain, as this should prompt suspicion of hypophosphatasia.