Abstract: e　To summarize the clinical and genetic characteristics of hypophosphatasia (HPP). Methods　The clinical data and results of peripheral blood high-throughput sequencing in 5 children with HPP as well as Sanger verification of the children and their relatives were retrospectively analyzed. Results　All 5 patients had poor bone mineralization and decreased serum alkaline phosphatase, and 3 patients had nervous system symptoms such as convulsion. Six mutation sites were identified in these 5 children by high-throughput sequencing, including c.346G>A (p.A116T), c.1097 to c.1099del CCT complex heterozygous mutation (p.T366_S367deli), c.1014 to c.1015ins G (p.H338fs), c.1446C>A (p.482H>Q) compound heterozygous mutations, c.920C>T (p.P307L) and c.883A>G (p.M295V). Among them, c.1014-c.1015ins g, c.1097-c.1099del CCT and c.1446c> A were reported for the first time. Protein structure was predicted to be potentially harmful, and ACMG rates them as possibly pathogenic. Conclusions　Five children were diagnosed with HPP and three new mutations were found, which enriched the human ALPL gene mutation database.

Key words: hypophosphatasia;　ALPL gene;　gene mutation