ESPE Abstracts

Background: Infantile hypophosphatasia (HPP) is an ultra-rare condition that may lead to debilitating morbidity and mortality. The prevalence of HPP in Indonesia is unknown. Enzyme replacement therapy or asfotase alfa, a bone-targeted recombinant alkaline phosphatase, can improve clinical outcome and prognosis of the patients, particularly those with severe type of HPP. The complications of HPP may be life-threatening and contribute to higher mortality in younger infants. In the absence and unavailability of asfotase alfa in Indonesia, supportive therapy becomes a sole management strategy in children and young infants with HPP.

Objective: To demonstrate clinical manifestation, complications, supportive management and its outcomes of the first reported case of infantile hypophosphatasia in Indonesia.

Case: A 7-month-old boy was admitted to the ICU due to severe pneumonia and prolonged fever. He was born prematurely at 36 weeks, 3640 gram from consanguineous parents. Since age 2 months, he was frequently hospitalised due to pneumonia. He had growth failure and global developmental delay. During hospital admission, his weight was 5800 gram and length was 58.5 cm (-5.69 SDS; U/l ratio 1.9), grade I hypertension, and fever. Physical examination showed enlarged fontanelle, microcephaly, chest deformity, and hypotonic extremities. Laboratory showed normal renal and liver tests, low thyroid function, hypercalcemia (serum Ca 11.2 mg/dL; ionised Ca 1.46 mmol/L), low serum ALP (10 U/L), increased serum B6 (>100 ng/mL) with normal magnesium, phosphate, and vitamin D25-OH. Echocardiography and head ultrasound were normal. Renal ultrasound showed nephrocalcinosis. Bone survey revealed multiple rib fractures, rickets-like appearance, and ‘tongues of radiolucency’ sign. He was diagnosed with hospital-acquired pneumonia, hypophosphatasia, and hypothyroid. Medical treatment included ventilatory support, levothyroxine, and intravenous antibiotics. During the current hospitalisation, he was put on tracheostomy and still ventilator-dependent due to bronchomalacia and airway clearance disorder. Genetic test showed homozygous ALPL mutation (c.98C>T (P.Ala33Val) and c.1099T>A (P.Ser367Thr)). Counseling was given to the parents with the most recent and feasible options of management. Ventilatory support strategy such as home ventilation becomes the most possible option to maintain the continuation of care and prolong the patient's survival.

Conclusion: The first reported case of infantile HPP in Indonesia showed significant and life-threatening complication such as persistent ventilator-dependent respiratory failure. Given the situation that asfotase alfa is not available in Indonesia, supportive management has become the only strategy to improve clinical outcomes and prognosis in the patient.