A case of infantile hypophosphatasia: Phenotypic findings of a compound heterozygous inheritance with a novel mutation

We report the case of a 9-month infant who presented with failure to thrive and bony deformities, mimicking a ricket-like picture. Biochemical parameters showed hypercalcemia, low serum alkaline phosphatase, normal serum phosphorus, magnesium, and parathormone levels. Ultrasound revealed nephrocalcinosis. Clinical exome sequencing revealed infantile hypophophatasia with two compound heterozygous mutations in exon 6 (mutation being novel) and 12. To the best of our knowledge, compound heterozygous mutations in exon 9 and exon 12 have presented with pyridoxine responsive seizure (PRS) along with hypophosphatasia (HPP). This is the third case of infantile HPP reported from India, but with a novel mutation who had not yet manifested with PRS.