ABSTRACT
Some authors have classifi ed YNS as a hereditary disorder, transmitted in an autosomal dominant fashion, while others have linked YNS to a variety of underlying diseases including connective tissue disease, malignancy, immunodefi ciency states, endocrine disorders including diabetes mellitus and thyroid dysfunction, or as an adverse drug effect (e.g., penicillamine, bucillamine, or gold sodium thiomalate). All three criteria may not be simultaneously present, and two of them have been judged to be suffi cient for diagnosis. The complete triad is seen in approximately 30% of cases. YNS is usually found between the fourth and sixth decades of life, while it is rarely seen in children.
