炭酸脱水酵素II欠損症 (大理石骨病, 尿細管性アシドーシス, 脳内石灰化) の大腿骨骨折治療経験

抄録

Osteopetrosis associated with renal tubular acidosis and cerebral calcification was established as an autosomal recessive inheritant syndrome, caused by a deficiency of carbonic anhydrase II (CA II) in 1983. Only 3 cases have been reported in Japan.
We describe a family with this syndrome. Proband is a 31 year old female, who presented with pathological fracture of the femoral, tibial and fibullar shafts, renal tubular acidosis and cerebral calcification. She was treated with intramedullary nailing and long leg cast followed by PTB brace. Bone biopsy was done from the iliac wing. Pathology showed irregular thickening of trabecular bone and unresorbed persistent calcified cartilage. Only a few osteoclast and fibroblast cells were found, suggesting poor bone remodeling.
Her two sisters are short and the elder one is affected with mild mental retardation. Both have osteopetrosis, renal tubular acidosis, cerebral calcification, and a history of long bone fracture. Her parents are not affected and not consanguineous. CA II activity was measured from erythrocyte hemolysates in all of the family. CA II activities from the mother, father, and three sisters were 57%, 40%, 13%, 15%, and 18% each, compared to the normal control. We consider these three sisters are homozygotes of CA II deficency and their parents heterozygotes.