Hypophosphatasia

Dr. Ayush PandeyMBBS,PG Diploma

December 10, 2018

March 06, 2020

Hypophosphatasia
Hypophosphatasia

What is Hypophosphatasia?

Hypophosphatasia is a rare genetic disorder in which there is an abnormal development of bones and teeth. It is due to a gene mutation that leads to low levels of a specific enzyme in the body.

What are its main signs and symptoms?

The symptoms of this disease may appear at birth, infancy, or adulthood. The growth and development of all major bones are affected, resulting in abnormally developed limbs in infants.

Based on the time of onset and symptoms, hypophosphatasia is known to have six clinical types.

What are its main causes?

Alkaline phosphatase is an enzyme that is needed for the normal development of bones and teeth. In patients of hypophosphatasia, there is a gene mutation that reduces or eliminates this enzyme. Alternatively, the mutation can cause an abnormally produced enzyme, which leads to hypophosphatasia.

A child is at risk of this condition if either one or both of his parents carry the defective gene.

How is it diagnosed and treated?

If a child or adult shows symptoms of hypophosphatasia, a blood test is carried out to check the levels of alkaline phosphatase.

  • For a final diagnosis, genetic tests are necessary to determine if there is a mutation in the gene.
  • Clinically, dental abnormalities are the most obvious sign of hypophosphatasia.
  • X-rays help to detect the skeletal abnormalities caused by the condition.

The treatment comprises of symptom management through medication, diet regulation, and physical therapy.

  • Calcium intake is reduced in the diet to balance the minerals in the body.
  • A child or an adult is advised physical therapy to prevent further degeneration of muscles and bones.
  • To tackle early tooth loss in children, dentures may have to be provided for missing teeth.
  • In severe cases, bone marrow transplantation is recommended, although its success is not certain.



References

  1. Science Direct (Elsevier) [Internet]; Hypophosphatasia
  2. Orphanet Journal of Rare Diseases. Hypophosphatasia. BioMed Central. [internet].
  3. Whyte MP. Hypophosphatasia - aetiology, nosology, pathogenesis, diagnosis and treatment. Nat Rev Endocrinol. 2016 Apr;12(4):233-46. PMID: 26893260
  4. Genetic home reference. Hypophosphatasia. USA.gov U.S. Department of Health & Human Services. [internet].
  5. National Organization for Rare Disorders. Hypophosphatasia. USA. [internet].