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Background & objectives: Mucopolysaccharidosis IVA (Morquio syndrome type A) is a lysosomal storage disorder caused by a mutation in the GALNS gene located on chromosome 16q24.3 and is inherited in an autosomal recessive manner. To date, more than 300 different mutations associated with MPS IVA, have been reported. Mutational heterogeneity can lead to difficulties in interpretation of molecular testing results, as novel mutations/variants of unknown significance may be detected relatively frequently. The purpose of this study is to analyze the GALNS mutations in Iranian MPS IVA patients.
Methods: Mutation screening of the GALNS gene was performed using direct sequence analysis on DNA samples from 8 unrelated Iranian MPS IVA patients.
Results: We have identified three novels and four previously reported mutations in 8 Iranian patients. We identified three novel missense mutations including: c.680T>C (p.F227S) in exon 7, c.G949C (p.G317R) and c.956G>C (p.R319T) in exon 9 in three different Iranian MPS IVA patients.  Bioinformatics analysis predicted the novel mutations as being disease-causing.
Conclusion: Our findings indicate the molecular heterogeneity of GALNS gene in Iranian patients. We also managed to find three new mutations of MPS IVA in Iranian patients, which are helpful in diagnosis, genetic counseling and prenatal diagnosis in affected families