Deteksi delesi south east asia (SEA), delesi sepanjang 3,7-kb dan 4,2-kb pada gen alpha-globin pembawa alpha-thalassemia

NAILIL HUSNA, Dr. Niken Satuti Nur Handayani, M.Sc.

2017 | Skripsi | S1 BIOLOGI

Alpha-thalassemia merupakan kelainan genetik yang menyebabkan gangguan pada sintesis rantai alpha-globin, subunit penyusun hemoglobin. Penyebab utama alpha-thalassemia adalah delesi pada satu atau lebih rantai alpha-globin. Delesi yang umum menyebabkan alpha-thalassemia yaitu delesi SEA (South East Asia), delesi sepanjang 3,7-kb dan 4,2-kb pada gen alpha-globin. Penelitian ini dilakukan untuk mendeteksi dan melakukan analisis kejadian tiga delesi tersebut pada 31 sampel yang diprediksi sebagai pembawa alpha-thalassemia berdasarkan uji hematologis Laboratorium Klinik Prodia. Tiga puluh satu sampel yang terbagi menjadi pembawa alpha-thalassemia dan pembawa alpha-thalassemia jenis ringan dilakukan uji molekuler multiplex gap-PCR untuk mengetahui genotipnya. Hasil uji molekuler diberbandingkan dengan prediksi uji hematologis. Sekuen dari alel mutan tiap sampel dianalisis untuk diketahui titik potong delesinya. Empat belas sampel telah terdeteksi tiga delesi tersebut meliputi delesi SEA pada dua sampel, delesi sepanjang 3,7-kb pada 10 sampel, delesi sepanjang 4,2-kb pada satu sampel, dan satu sampel mengalami delesi ganda ganda dengan ditemukan delesi 3,7-kb dan 4,2-kb. Titik potong delesi SEA ujung 5 pada basa nomor 165.396 dan ujung 3 pada basa nomor 184.699 dari kromosom 16, titik potong delesi -3,7-kb berada pada basa nomor 252 hingga 428 dari sekuen sekuen homolog Z, dan titik potong delesi 4,2-kb berada pada basa nomor 45 hingga 366 dari sekuen sekuen homolog X pada kromosom 16. Hasil prediksi uji hematologis menunjukkan kesesuaian dengan hasil uji molekuler pada 12 sampel.

alpha-thalassemia is a genetic disorder interrupting alpha-globin chain synthesis which is one of haemoglobin component. It is caused by deletion of one or more alpha-globin gene. SEA (South East Asia) deletion, 3,7-kb deletion and 4,2-kb deletion are the most common deletion detected. The aims of this research are to detect those three deletions in 31 samples predicted as alpha-thalassemia carrier based on its haematological parameter by Laboratorium Klinik Prodia. The Three deletions was analysed its DNA sequence to determine the breakpoint site. The samples were divided into alpha-thalassemia traits and alpha-thalassemia silent trait. Multiplex gap-PCR was applied to determine the genotypes. The genotype was compared to the prediction of haematological parameters. The breakpoint site was analysed by DNA sequencing. Out of 31 samples, 14 samples were confirmed its genotypes, they are two samples with heterozygous for SEA deletion, 10 samples with heterozygous for 3,7-kb deletion, one samples with 4,2-kb deletion in heterozygous states and one sample occurred double heterozygous caused by 3,7-kb and 4,2-kb deletion. The 5 end breakpoint of SEA deletion located at nucleotide number 165.396 and the 3 end breakpoint is at nucleotide number 184.699 of chromosome number 16. The boundaries of 3,7-kb and 4,2-kb deletion presented in short ranges that are within nucleotide number 252 to 429 of Z box of chromosome number 16 for 3,7-kb deletion, and within nucleotide number 47 to 367 of Z box of chromosome number 16 for 4,2-kb deletion. The haematological prediction and molecular confirmation showed same result in 12 samples.

Kata Kunci : alpha-thalassemia, delesi SEA, delesi 3,7-kb, delesi 4,2-kb.