Congenital contractural arachnodactyly (CCA) is caused by mutations in the gene for fibrillin 2 glycoprotein, a component of connective tissue. The causes of osteodystrophy or osteodysplasia in CCA are unknown. We report bone metabolism in a 28 month-old girl with CCA. Serum alkaline phosphatase and osteocalcin levels were 650 IU/l and 22 ng/ml at 1.5 months old (control: 530+/-65, 16.5+/-4.3), and 580 IU/l and 21 ng/ml at 28 months old (control: 465+/-58, 15.0+/-3.5), i.e. in upper-normal levels. The urinary pyridinoline and deoxypyridinoline levels were 1176 and 194 micromol/mol creatinine at 1.5 months old (control: 329+/-76, 63+/-12), and 407 and 111 micromol/mol cr at 28 months old (control: 231+/-49, 50+/-11), apparently higher than the control values. These findings may indicate that abnormal fibrillin may impair bone metabolism and cause the osteodystrophy or osteodysplasia in CCA.