A child presented with clinical features of rickets but low level of serum alkaline phosphatase. He has the following condition:

Hypophosphatasia is a rare autosomal recessive condition characterized by deficiency of alkaline phosphatase activity in serum, bone, and tissues. Enzyme deficiency leads to poor skeletal mineralization with clinical and radiographic features similar to rickets. Diagnosis is made by demonstrating elevated urinary phosphoethanolamine associated with low serum alkaline phosphatase.Alkaline phosphatases are primarily found in liver, bone, intestines, kidney, and placenta. It increased in,Obstructive hepatobiliary diseaseBone disease (physiologic bone growth, Paget disease, osteomalacia, osteogenic sarcoma, bone metastases)HyperparathyroidismRicketsBenign familial hyperphosphatasemiaPregnancy (third trimester)GI disease (perforated ulcer or bowel infarct)Hepatotoxic drugsRef: Zeitler P.S., Travers S.H., Nadeau K., Barker J.M., Kelsey M.M., Kappy M.S. (2012). Chapter 34. Endocrine Disorders. In W.W. Hay, Jr., M.J. Levin, R.R. Deterding, J.J. Ross, J.M. Sondheimer (Eds), CURRENT Diagnosis & Treatment: Pediatrics, 21e.