We read with interest the report of Fujimoto and Horowitz (1983) about two sibs with mild manifestations of Morquio syndrome. Recently we evaluated a 13-10/12-year-old boy who was referred because of nonresolving bilateral Legg-Perthes disease (Fig. 1). His height (Tanner stadiometer) was 149.2 cm (15th percentile for age and sex), head circumference 56.2 cm, and span 161.4 cm. He had an attractive face without midface hypoplasia or coarsening. There was no evidence of corneal clouding by slit-lamp examination. He had full range of movement at all joints except the hips. Pectus carinatum and organomegaly were absent. He had shortening of the trunk with an upper/lower ratio of 0.84, but he did not have disproportionate short stature. Lumbar lordosis was normal. The knees were prominent but genu valgum was absent. Hands and fingers were well proportioned. Ligamentous laxity was not excessive. Muscle strength, tone, and deep tendon reflexes were normal. He had a widely based, stiff-hip gait. Roentgenograms showed mild platyspondyly, anterior wedging of the first lumbar vertebra, abnormal capital femoral epiphyses (Fig. l), and minimal odontoid hypoplasia. There was no shortness of tubular bones, nor evident dysostosis multiplex.
Metabolic studies showed nondetectable activity of the N-acetylgalactosamine-6-sulfate sulfatase in white blood cells and 1.83 U/mg protein/hr (normal = greater than 3 U/mg proteindhour) in fibroblasts. Urine keratin sulfate was 22.9 mghotal volume (normal range is less than 2 mg/total volume). The diagnosis of Morquio syndrome was made.
The enzymatic and clinical findings in our case, that of Fujimoto and Horowitz [ 19831, and two cases described by Holzgreve et al [ 19811 confirm that there is a mild form of the Morquio syndrome. Our patient presented with long-standing Legg-Perthes disease. Bilateral involvement occurs in approximately 10-12 % of Legg-Perthes cases. In our experience, some patients in this group have misdiagnosed multiple epiphyseal dysplasia. The findings in our case and another recently evaluated