Hypophosphatasia: 90 Years from a Canadian Discovery—A Comprehensive Review of the ALPL Gene Underlying Rathbun’s Syndrome

Hypophosphatasia (HPP) is an exceptional genetic bone disorder of metabolic character caused by a deficit of the tissue-nonspecific alkaline phosphatase isoenzyme (TNSALP). This protein is encoded by the <i>ALPL</i> (alkaline phosphatase liver/bone/kidney) gene. In the medical literature, HPP is also known as Rathbun's syndrome, named after the Canadian physician who first identified this disorder. Patients exhibit persistently low serum alkaline phosphatase (ALP) levels. In fact, ALP renders this measure a reliable indicator of the condition. Adult HPP is varied, with some patients exhibiting only moderate, non-pathognomonic symptoms. They include arthropathy, arthrodynia, chondrocalcinosis, osteopenia, osteomalacia, and generic musculoskeletal discomfort. Healthcare may require coordinating several services to manage a patient with HPP. This comprehensive review will highlight the genetic knowledge, pathology data, and patient management approaches, including Medicare's coverage. In addition, this paper aims to address specific themes related to HPP, including its significance, current challenges, and controversies.