Mucopolysaccharidosis II (MPS II, Hunter syndrome) is a rare, X-linked, recessive lysosomal storage disease caused by a deficiency of enzyme iduronate-2-sulfatase (I2S), encoded by IDS gene. I2S enzyme catalyzes the degradation of glycosaminoglycans (GAGs), such as dermatan sulfate (DS) and heparan sulfate (HS). Deficiency of I2S leads to the accumulation of these glycosaminoglycans in the tissues. Exon-specific analyses of IDS exon 8 has been analyzed from eight MPS II Indonesian patients at Cipto Mangunkusumo National Referral Hospital, Jakarta, Indonesia. Identification of IDS exon 8 was performed using PCR and sequencing-based methods. One previously reported deletion mutation (c.1023delA) of exon 8 was identified amongst the patients, causing a frameshift in the corresponding amino acid sequence (p.Glu341AspfsTer19), observed in one patients. This mutation causes a reduction in the number of amino acids and changes in the structure of 3D proteins. There is no reduction and change in the active site of the protein, but the termination that occurs at the 359th codon causes a reduction of two glycosylation sites. This study provides the first mutation analysis of exon 8 of IDS, and successfully identified mutations within the IDS gene that may be associated with MPS II. This supports the feasibility of early diagnosis and screening for MPS II in the future.