Table 5.

Acquired Disorders and Disorders of Unknown Cause in the Differential Diagnosis of Adult-Onset Hypophosphatasia and Odontohypophosphatasia

DisorderClinical Features / Comment
Osteoarthritis & pseudogout (secondary to calcium pyrophosphate dehydrate deposition)Both are presentations of adult hypophosphatasia, distinguished from the more common disorders by clinical history & lab findings.
Osteopenia/osteoporosis Must be distinguished from adult hypophosphatasia, in that bisphosphonates may be contraindicated (See Management, Agents/Circumstances to Avoid.)
Periodontal disease May be difficult to distinguish from hypophosphatasia, in that alveolar bone loss can be seen w/severe gingivitis. However, gingival inflammation is unusual w/odontohypophosphatasia.
Adult pseudohypophosphatasia Characterized by clinical, biochemical, & radiographic findings reminiscent of adult hypophosphatasia, w/exception that clinical lab assays of serum ALP activity are in normal range.

ALP = alkaline phosphatase

From: Hypophosphatasia

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