Metaphyseal peg in geroderma osteodysplasticum: a new genetic bone marker and a specific finding?

We describe two sibs with geroderma osteodysplasticum (GO) who, in addition to the known clinical and radiologic manifestations of the disorder, presented a metaphyseal peg indenting the epiphysis of the long bones, particularly at the knees. The peg was visible only at the age of 4 to 5 years but was invisible in infancy and following physeal closure. This may explain why this anomaly was not described in previous reports of 23 patients in 11 families with GO. The metaphyseal peg is an abnormality of bone development so far unknown to us. We speculate that it represents a primary, agedependent alteration of bone shape and hence a new genetic bone marker apparently specific to GO.