The desease is very rare and occurs sporadically, but it has occured in siblings. The skin lesions contain chondroitin cells embedded in amorphous eosinophilic ground substance in the dermis. In the early lesions this consists of glycosaminoglican, but in the later lesions in the matrix is mainly composed of chondroitin sulfate. The dermal collagen is decreased and the collagen fibrils are fewer and thinner then in normal skin. The hyaline material may also be present in the muscles and bones.
Skin lesions are present at birth or developin early childhood.
There may be small pearly papules or nodules, particulary on the face or neck. These may be hard or soft, fixed or mobile, and they may ulcerate. Gingival hypertrophy is commonly present, and flexion contractures of the fingers,elbows, hips and knees may develop. Osteolytic lesions can occur in the skull, long bones or phalanges. The musculature is poorly developed.