Mutation identification of unreported and reported mutation profile in exon 7 of N-Acetylgalactosamine-6-Sulfates (GALNS) gene of mucopolysaccharidosis type IV A (MPS IVA) patients in Indonesia

Mucopolysaccharidosis type IVA (MPS IVA), is an autosomal recessive genetic disorder because of N-acetylgalactosamine-6-sulfate deficiency which causes keratan sulfate and chondroitin sulfate to not degrade in lysosome. MPS IVA was caused of GALNS gene which located in chromosome 16q24.3 with the most frequent mutation occurrence in exon 7. There are no report or publication about MPS IVA or GALNS gene mutation in Indonesia, therefore this research is aimed to analyze the mutation profile in exon 7 of the GALNS gene in MPS IVA patients in Indonesia. The DNA from blood samples of four patients and three control samples from RSUPN Cipto Mangunkusumo were analyzed. Amplification by polymerase chain reaction was done after designing the primer. Furthermore, electrophoresis and sequencing analysis has been performed. The result shows that there is silent mutation c.708C>T and nonsense mutation c.751C>T. The silent mutation is categorized as a benign variant, while the nonsense mutation is categorized as a pathogenic variant because it may affect protein features and cause neuromuscular disorder. The silent and nonsense mutation that were found were already reported by Laradi and Morrone, but has not been reported in Indonesia. Further experiment was needed to find other mutation in other genes.