Transient hyperphosphatemia: a benign laboratory disorder in a boy with Gitelman syndrome

Transient hyperphosphatasemia of infancy and early childhood (THI) is characterized by transiently increased activity of serum alkaline phosphatase (S-ALP), predominantly its bone or liver isoform, in children under five years of age. There are no signs of metabolic bone disease or hepatopathy corresponding with the increased S-ALP. THI is benign disorder, rather laboratory than clinical disorder, which is usually accidentally detected in both healthy and sick children. When encountered in a child with either chronic bone, liver or kidney disease, it might concern the physician. We present a three year old boy with genetically confirmed Gitelman syndrome where THI was detected accidentally during periodic check-up. S-ALP peaked to 41.8 µkat/L, there were neither laboratory or clinical signs of liver or bone disease; the S-ALP dropped to normal value of 4 µkat/L 60 days later. Therefore, the patient fulfilled the criteria for THI. There were no further increases in S-ALP.