Deficiency in lysosomal enzyme N-acetylgalactosamine-4-sulfatase (arylsulfatase B); results in deficient degeneration of keratan sulfate. Condition is autosomal recessive. Onset occurs at 2-4 years of age, with aortic valve degeneration and dysostosis multiplex. Disorder may be mild (relatively long survival) or severe (death by 30 years of age.)