Question: What is (are) Hypophosphatasia ?
Answer: Hypophosphatasia (HPP) is a genetic condition that causes abnormal development of the bones and teeth. The severity of HPP can vary widely, from fetal death to fractures that don't begin until adulthood. Signs and symptoms may include poor feeding and respiratory problems in infancy; short stature; weak and soft bones; short limbs; other skeletal abnormalities; and hypercalcemia. Complications can be life-threatening. The mildest form of the condition, called odontohypophosphatasia, only affects the teeth. HPP is caused by mutations in the ALPL gene. Perinatal (onset before birth) and infantile HPP are inherited in an autosomal recessive manner. The milder forms, especially adult forms and odontohypophosphatasia, may be inherited in an autosomal recessive or autosomal dominant manner. While treatment has always been symptomatic and supportive, recently an enzyme replacement therapy (ERT) called asfotase alfa has been show to improve bone manifestations people with childhood onset HPP and has been approved by the FDA.
Source: GARD

Question: What causes Hypophosphatasia ?
Answer: What causes hypophosphatasia? Hypophosphatasia (HPP) is a genetic condition caused by mutations in the ALPL gene. This gene gives the body instructions to make an enzyme called alkaline phosphatase, which is needed for mineralization of the bones and teeth. Mutations in this gene lead to an abnormal version of the enzyme, thus affecting the mineralization process. A shortage of the enzyme also causes other substances to build up in the body. These abnormalities lead to the features of HPP. ALPL mutations that almost completely eliminate alkaline phosphatase activity generally cause the more severe forms of HPP, while mutations that reduce activity to a lesser extent often cause the milder forms of HPP.
Source: GARD

Question: What are the treatments for Hypophosphatasia ?
Answer: How might hypophosphatasia be treated? Until recently, management of hypophosphatasia (HPP) has mostly been aimed at addressing symptoms of the condition. For example: Hydration, restriction of dietary calcium, vitamin D, and sometimes thiazide diuretics for hypercalcemia Ventilatory support for severely affected infants, some of which need a tracheostomy, which can lead to problems with speech and language development and tolerance of oral feeds Physiotherapy, occupational therapy and chronic pain management for pain and motor difficulty Surgery for fractures that fail to heal More recently, research has shown positive effects of human recombinant enzyme replacement therapy (ERT), called asfotase alfa, on people who began having symptoms before 6 months of age. There reportedly have been significant improvements in the X-ray appearances of bone tissue, along with improvements in growth, respiratory function, motor development and calcium homeostasis after 612 months of treatment. The children in the original study have now received more than three years of treatment, without apparent major side effects, and with continuing improvement in affected systems. Asfotase alfa appears to be a valuable emerging therapy for the treatment of bone manifestations in people with pediatric-onset HPP. In October of 2015 the FDA approved asfotase alfa, sold as Strensiq. Bone marrow and stem cell transplantation in infancy and childhood have improved the severity of the disease, but have not provided long term improvement.
Source: GARD