Mucopolysaccharidosis IVA (MPS IVA; Morquio A syndrome) is a lysosomal storage disease caused by deficiency of N-acetylgalactosamine-6-sulfatase (GALNS) and transmitted as an autosomal recessive trait. This is the first systematic mutation screen in Chinese MPS IVA patients. Mutation detections in 24 unrelated Chinese MPS IVA patients were performed by PCR and direct sequencing of exons or the mRNA of GALNS. A total of 42 mutant alleles were identified, belonging to 27 different mutations. Out of the 27 mutations, 16 were novel, including 2 splicing mutations (c.567-1G>T and c.634-1G>A), 2 nonsense mutations (p.W325X and p.Q422X) and 12 missense mutations (p.T88I, p.H142R, p.P163H, p.G168L, p.H236D, p.N289S, p.T312A, p.G316V, p.A324E, p.L366P, p.Q422K and p.F452L). p.G340D was found to be a common mutation in the Chinese MPS IVA patients, accounting for 16.7% of the total number of mutant alleles. The results show that the mutations in Chinese MPS IVA patients are also family specific but have a different mutation spectrum as compared to those of other populations.