Tesis

Profil Aktivitas Enzim Iduronat-2-Sulfatase dan Kaitannya dengan Varian Gen Iduronat-2-Sulfatase pada Pasien Mukopolisakaridosis Tipe II di Indonesia = Profile of Iduronate-2-Sulfatase Activities and Its Relationship with Iduronate-2-Sulfatase Gene Variants of Mucopolysaccharidosis type II Patients in Indonesia .

Latar belakang: Mukopolisakaridosis (MPS) tipe II adalah kelainan genetik yang ditandai dengan gangguan metabolik berupa defisiensi enzim iduronat-2-sulfatase (I2S) karena adanya mutasi pada gen iduronat-2-sulfatase (IDS), sehingga heparan sulfat dan dermatan sulfat tidak terdegradasi dan terakumulasi pada jaringan. Penelitian ini dilakukan untuk menganalisis aktivitas spesifik enzim I2S dan kaitannya dengan varian mutasi gen IDS pada pasien MPS II di Indonesia. Metode: Data sekuen nukleotida gen IDS dari enam pasien MPS II dianalisis untuk melihat jenis mutasi serta dibuat model konformasi proteinnya. Sel peripheral blood mononuclear cell (PBMC) diisolasi menggunakan metode sentrifugasi bertingkat dan dikultur menggunakan medium RPMI. Nilai aktivitas spesifik I2S diperoleh dengan mengukur aktivitas I2S per miligram konsentrasi total protein. Aktivitas enzim I2S diukur menggunakan metode fluorometri, sementara konsentrasi total protein diukur menggunakan bicinchoninic acid (BCA) protein assay. Hasil: Tiga varian mutasi yang ditemukan pada pasien MPS tipe II adalah missense (3/6), delesi (2/6), dan nonsense (1/6). Aktivitas enzim spesifik I2S pada pasien menunjukkan angka yang bervariasi. Mutasi dengan rata-rata aktivitas spesifik I2S paling rendah sampai paling tinggi secara berurutan adalah mutasi delesi (0,026 nmol/min/mg), missense (0,052 nmol/min/mg), dan nonsense (0,052 nmol/min/mg). Kesimpulan: Aktivitas spesifik enzim I2S pada pasien MPS tipe II di Indonesia 0,044 nmol/min/mg, sedangkan pada kontrol adalah 0,172 nmol/min/mg. Nilai rata-rata aktivitas spesifik I2S pada pasien menurun empat kali lipat dibandingkan pada kontrol.
Kata kunci: MPS tipe II, iduronat-2-sulfatase, enzim I2S, gen IDS


Background: Mucopolysaccharidosis type II (MPS II) is an inherited metabolic disorder that caused by iduronate-2-sulfatase (I2S) enzyme deficiency due to mutations in the iduronate-2-sulfatase (IDS) gene, so that heparan sulfate and dermatan sulfate do not be degrade and accumulate in tissues. This study was conducted to analyze the specific activity of I2S and its relationship to IDS variant mutation of MPS II patients in Indonesia. Method: IDS gene nucleotide sequences from six MPS II patients were analyzed to see mutation type and protein conformation model was made. Peripheral blood mononuclear cell (PBMC) were isolated using a stratified centrifugation and cultured using the RPMI medium. I2S specific activity values are obtained by measuring I2S activity per milligram of total protein concentration. I2S enzyme activity was measured using fluorometry method, while total protein concentration was measured using bicinchoninic acid (BCA) protein assay. Result: There were three variant mutation in MPS II patients, such as missense (3/6), deletion (2/6), and nonsense (1/6). I2S specific enzyme activity shows varying numbers. IDS mutation based on I2S specific activity from lowest to highest mean value are deletion (0.026 nmol/min/mg), missense (0.052 nmol/min/mg), and nonsense (0.052 nmol/min/mg). Conclusion: I2S specific activity in MPS II patient is 0,044 nmol/min/mg, while the control is 0,172 nmol/min/mg based on the mean value. I2S specific activity in patients decreased four times compared to controls
Keywords: MPS II, iduronate-2-sulfatase, I2S enzyme, IDS gene