Hyperechoic metaphyses in hypophosphatasia: what does it mean?

We report a case of hypophosphatasiadiagnosed using US and CT at 29 weeks’ gestation and confirmed by molecular analysis. Prenatal US revealed very short fetal limbs and severe demineralizationof the skull. The diaphyses were normal, but the metaphysesof the long bonesappeared hyperechoic with no posterior shadowing. No fractures or long- bone deformationswere observed. Three-dimensional helical CT performed at 29 weeks’ gestation provided additional details of the abnormal bones, i.e. irregular and cupped metaphysesthat were very similar to the radiological findings of hypophosphatasiadescribed postnatally. To our knowledge, the description of hyperechoic metaphysesin hypophosphatasiais unique and is a consequence of abnormal mineralization of the metaphysesthat is specific to this pathology.