At the age of 1 year and 9 months, biochemical analysis showed borderline high (but within normal range) levels of serum calcium (11.0 mg/dL; reference values (RV): 9–11 mg/dL) and phosphorus (6.3 mg/dL; RV: 3.4–6.2 mg/dL), reduced ALP levels (34 U/L; RV: 70–350 U/L), and elevated levels of vitamin B6 (250 μg/L; RV: 5.2–34.1 μg/L), supporting the diagnosis of HPP. This evidence concerns the gene ALPP and hypophosphatasia.