Genetic Assessment of Mucopolysaccharidosis Type IV and the First Pathological Mutation of c.313A>G in the Iranian Population

Morquio syndrome is a mucopolysaccharidosis (type 4) that has autosomal recessive inheritance. Moreover, it is caused by defects in the two genes; GALNS (Murcio A) and GLB1 (Murcio B). The prevalence rate of this condition is estimated to be about 1 per 200000 live births globally. Besides, Middle Eastern cases shape the greatest ratio, due to higher rates of consanguineous marriages. The most frequent clinical manifestations of the disease include skeletal abnormalities, hearing and vision problems, decreased physical growth, and cardiac malformations.

This study investigated the pathogenic mutations in two Iranian individuals. Both cases were the result of consanguineous marriages with mucopolysaccharidosis type 4 (A or B types, each). Following of genomic DNA extraction, Whole Exome Sequencing was conducted for the study patients. Then, for the validation of observed pathogenic mutations, sanger sequencing was performed for the patients.

 Two explored patients demonstrated homozygote mutations. Mutation analysis of the GLB1 gene revealed c.443G>A mutation in one patient and GALNS gene c.313A>G in the other.

Two pathogenic mutations in GLB1 and GALNS gene were found in 2 Iranian patients in this study. The NGS was a desirable and reliable technique for detecting these two mutations. The c.313A> G mutation in the GALNS gene was novel and had not been reported in the world.