FIXED THORACIC KYPHOSIS IN JUVENILES AND YOUNG ADULTS. MASKED MUCOPOLYSACCHARIDOSIS (MPS) VII

Abstract

We previously reported the chance finding of Alder type granulations in leukocytes of 19 and 16 year-old brothers (R. Gitzelmann et al., Helv.paediat.Acta 33:413-428,1978). The only physical sign was a fixed kyphosis of the thoracic spine without discomfort. X-ray findings were modest, urinary acid mucopolysaccharides increased. Degradation of sulphated mucopolysaccharides by cultured skin fibroblasts was slowed, β-glucuronidase activity in serum, leukocytes and fibroblasts abnormally low thus documenting MPS VII. We speculated that this previously unknown late and mild form of MPS VII may exist undetected in the general population. We have now discovered a 15 1/2 year-old boy with a history of nervous dysfunction and pains who had Alder type granulations. From age 9 1/2 to 15 he suffered from back pain. He was minimally hunch-backed at 10 1/2 years. Today, he has a partially fixed thoracic kyphosis and complains of a tired back after heavy lifting. β-Glucuronidase was abnormally low in his serum and leukocytes. The parents' β-glucuronidase was normal in serum but intermediate in leukocytes. These observations document MPS VII as the first monogenic disorder of metabolism known to cause fixed thoracic kyphosis in seemingly healthy juveniles and young adults. As the course of this form of MPS VII is unknown, a search for further patients in young and older adults seems warranted.