To the Editor:

We thank Ms Li and Dr. Thorne for bringing to our attention their report describing the adult phenotype of Stickler syndrome type III in a 3-generation pedigree affected by osteoarthritis. Unlike the 2 families we describe with premature arthritis due to a type II collagen mutation, the family described by Li and Thorne harbors a COL11A2 mutation. It is not surprising, however, that mutations in this gene lead to a similar phenotype, given the close physical association between type II, type IX, and type XI collagen fibers in the cartilage extracellular matrix. We chose to highlight our 2 families because their phenotype is primarily joint restricted and characterized by a lack of any traditional type II collagenopathy phenotype features such as mid-facial hypoplasia, Pierre-Robin sequence, hearing loss, or ocular abnormalities. Although the consensus clinical criteria for Stickler syndrome vary (Freddi S, Savarirayan R, Bateman JF. Molecular diagnosis of Stickler syndrome: a COL2A1 stop codon mutation screening strategy that is not compromised by mutant mRNA instability. Am J Med Genet 2000;90:398–406), neither of our 2 families would meet the diagnostic criteria. We agree, however, that type XI mutation analysis should also be considered in a family presenting with an autosomal-dominant pattern of premature arthritis.

Peter Kannu MB ChB, DCH, FRACP* †, John F. Bateman BSc Hon, PhD‡, Ravi Savarirayan MBBS, MD, FRACP, HGSA, ARCPA§, * Murdoch Childrens Research Institute, University of Melbourne and Genetic Health Services Victoria, Parkville, Melbourne, Australia, † Queen's University, Kingston, Ontario, Canada, ‡ Murdoch Childrens Research Institute, Parkville, Melbourne, Australia, § Murdoch Childrens Research Institute, University of Melbourne, and Genetic Health Services Victoria, Parkville, Melbourne, Australia.