Lethal hypophosphatasia, spur type: case report and fetopathological study: Hypophosphatasia (HP) is characterised by severe undermineralisation of the skeleton owing to deficiency of tissue nonspecific alkaline phosphatase. Clinically a perinatal, infantile, childhood and adult type is distinguished. Clinical signs in the perinatal type of HP show considerable overlap with other skeletal dysplasias such as osteogenesis imperfecta type IIA and type IIC, and achondrogenesis type IA. If present, "spurs" of the limbs are diagnostic for HP. We present a prenatally diagnosed case of HP and discuss the differential diagnosis based on clinical, radiological and pathological findings. Our findings indicate that two types of spurs can be distinguished in hypophosphatasia: midshaft type and joint type.