Hypophosphatasia (HPP) is a rare inherited disease caused by a loss of function mutation within the gene ALPL encoding the tissue nonspecific alkaline phosphatase (TNSALP).1 Deficient alkaline phosphatase (ALP) activity leads to an accumulation of its substrates including pyridoxal‐5‐phosphate (PLP) and inorganic pyrophosphate (PPi). The gene discussed is ALPL; the disease is hypophosphatasia.