The patient is a north african female, fourth born child in a family with consanguinity. Facial dysmorphia, clubfeet, swollen extremities and heel borne ponctuate calcifications are observed soon after birth. beta glucuronidase activity is very low in serum, leukocytes and skin fibroblasts. At 18 months, gorwth and psychomotor development are normal. Flat facies and dorsolumbar cyphosis are striking. There is no clinical sign of storage disease, neither ocular or cytologic (blood, bone-marrow) abnormalities. Squeletal abnormalities are predominant on cervical and lumbar column and pelvis. Urinary excretion of chondroitin 4 sulfate and chondroitin 6 sulfate is increased. A 4 year old sister is affected. Facial dysmorphia, mild squeletal abnormalities are observed. Again, growth is normal and there is no symptom of storage disease. Enzymic expression of parent heterozygotism is marked in serum studies, but less marked in leukocytes and fibroblasts. The last two children are heterozygotes. At the time of a 5th pregnancy, enzymic activity studies of amniotic fluid and amniotic cells have shown that the foetus was an inaffected female. This child was normal at birth.