Thursday, 19 April 2018

Infantile Hypophosphatasia in Saudi Child. Case Report

AHypophosphatasia is characterized by low serum alkaline phosphatase (ALP) activity and has a similar radiographic appearance with rickets. There are considerable differences in the severity of the disease. The clinical course of this condition often improves; although early death can occur in the infantile form of the disorder. We experienced one case with severe infantile type of hypophosphatasia.

Hypophosphatasia (HPP) characterized by defective mineralization of bone and dental tissue. The features of this disease include diminished alkaline phosphatase (ALP) activity and increased urinary excretion of Phosphorylethanolamine. This inborn error of metabolism is a rare inherited form of rickets or osteomalacia due to reduced activity of tissue-nonspecific alkaline phosphatase (TNSALP) caused by loss-of-function mutation within the TNSALP gene marked by low serum ALP. HPP is classified into different clinical types with a remarkable range of severity. Perinatal HPP is always fatal from profound skeletal hypomineralization. Infantile HPP presents before six months of age with rickets, failure-to-thrive and hypercalcemia occasionally, craniosynostosis or vitamin B6-responsive seizures as well as respiratory failure associated with progressive chest deformity. Childhood HPP features rickets and loss of deciduous teeth, hypoplasia and myopathy while adult HPP causes osteomalacia.

Autosomal recessive inheritance accounts for severe HPP while autosomal dominant or recessive transmission underlies the mild form. TNSALP replacement therapy is an effective treatment of HPP in infants. The mortality rate of infantile type is 50–100% and patients die due to respiratory infection. We present a case of a 14-month-old girl with the clinical manifestations of rickets, failure to thrive and developmental delay. Hypercalcaemia and low alkaline phosphatase level constitute the main diagnostic laboratory abnormalities if infantile HPP. We aim to share experience.

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