hypophosphatasia

Also known as childhood hypophosphatasia (disorder), deficiency of alkaline phosphatase (disorder), deficiency of alkaline phosphatase (disorder) [Ambiguous], hypophospatasia, childhood, childhood hypophosphatasia, deficiency of alkaline phosphatase, Rathburn disease, Phosphoethanolaminuria

Hypophosphatasia (; also called deficiency of alkaline phosphatase, phosphoethanolaminuria, or '''Rathbun's syndrome; sometimes abbreviated HPP''') is a rare, and sometimes fatal, inherited metabolic bone disease. Clinical symptoms are heterogeneous, ranging from the rapidly fatal, perinatal variant, with profound skeletal hypomineralization, respiratory compromise or vitamin B6 dependent seizures to a milder, progressive osteomalacia later in life. Tissue non-specific alkaline phosphatase (TNSALP) deficiency in osteoblasts and chondrocytes impairs bone mineralization, leading to rickets or os

Key facts

Medical condition.name: Hypophosphatasia
Medical condition.image: 1ALK.png
Medical condition.caption: Ribbon diagram of the alkaline phosphatase protein, which is deficient in individuals with hypophosphatasia
Medical condition.field: Orthopedics, pediatrics, endocrinology
Medical condition.synonyms: Phosphoethanolaminuria; Rathbun's syndrome
Medical condition.symptoms: Variable—may include osteopenia, skeletal hypomineralization, respiratory compromise
Medical condition.onset: Birth
Medical condition.onset_always: y
Medical condition.duration: Lifelong
Medical condition.types: Infantile, childhood, adult, and odontohypophosphatasia
Medical condition.causes: Mutation of the ALPL gene

Article

19 sections

Contents

Symptoms and signs
Perinatal hypophosphatasia
Infantile hypophosphatasia
Childhood hypophosphatasia
Adult hypophosphatasia
Odontohypophosphatasia
Causes
Genetics
Diagnosis
Dental findings
Laboratory testing
Radiography
Genetic analysis
Treatment
History
See also
References
Further reading
External links

Hypophosphatasia (; also called deficiency of alkaline phosphatase, phosphoethanolaminuria, or '''Rathbun's syndrome; sometimes abbreviated HPP') is a rare, and sometimes fatal, inherited metabolic bone disease. Clinical symptoms are heterogeneous, ranging from the rapidly fatal, perinatal variant, with profound skeletal hypomineralization, respiratory compromise or vitamin B6 dependent seizures to a milder, progressive osteomalacia later in life. Tissue non-specific alkaline phosphatase (TNSALP) deficiency in osteoblasts and chondrocytes impairs bone mineralization, leading to rickets or osteomalacia. The pathognomonic finding is subnormal serum activity of the TNSALP enzyme, which is caused by one of 388 genetic mutations identified to date, in the gene encoding TNSALP. Genetic inheritance is autosomal recessive for the perinatal and infantile forms but either autosomal recessive or autosomal dominant in the milder forms.

The prevalence of hypophosphatasia is not known; one study estimated the live birth incidence of severe forms to be 1:100,000. and some studies report a higher prevalence of milder disease.