Thalassemia is an inherited disorder of autosomal recessive gene caused by decrease or absent production of one or two type of globin chain. This disorder will affect the quality and quantity of blood production. In Indonesia, thalassemia is not concerned as urgency, although it lies in thalassemia belt area. Thalassemia is classified according to the particular globin chain which affected such as a-thalassemia and b-thalassemia. Besides thalassemia, there are variant hemoglobinopathy called HbE. The aim of this study was to assess the prevalence of thalassemia carriers among the volunteer of screening in Yogyakarta Special Region from 2012 until 2015. The thalassemia carrier screening was conducted by collaborating with Indonesian Association of Parents of Children with Thalassemia (APCT) Yogyakarta. The hematological measurement and High-Performance Liquid Chromatography (HPLC) were performed on Prodia Laboratory Yogyakarta. The analysis of carriers prevalence was conducted in Laboratory of Genetics and Breeding, Faculty of Biology, Universitas Gadjah Mada, Yogyakarta. Among 241 volunteers, we found 44 volunteers was diagnosed as b-thalassemia carrier, 30 volunteers as a-thalassemia carrier as well as HbE disorder carrier, and 1 volunteer was diagnosed as a-b-thalassemia carrier. The number of thalassemia carrier shows no significant difference each year. The prevalence of thalassemia carrier is high, even though the distribution is limited by the location where the screening took place. ABSTRAKThalassemia adalah kelainan bawaan pada gen resesif autosomal akibat penurunan atau tidak diproduksinya satu atau dua jenis rantai globin. Kelainan ini mempengaruhi kualitas dan kuantitas produksi darah. Di Indonesia, thalasemia belum menjadi masalah penting walaupun lokasinya termasuk dalam daerah sabuk thalasemia. Thalasemia diklasifikasikan berdasarkan rantai globin yang mengalami mutasi yaitu a-thalasemia dan b-thalasemia. Selain thalasemia, ada satu varian hemoglobinopati yang disebut HbE. Tujuan dari penelitian ini adalah untuk menentukan prevalensi thalasemia di antara relawan skrining di Daerah Istimewa Yogyakarta dari tahun 2012 sampai 2015. Skening thalasemia dilakukan dengan bekerjasama Perhimpunan Orang tua Penderita Thalasemia Indonesia (POPTI), Daerah Istimewa Yogyakarta. Pemeriksaan hematologi dan High-Performance Liquid Chromatography (HPLC) dilakukan di Laboratorum Klinik Prodia, Yogyakarta. Analisis prevalensi pembawa gen thalasemia dilakukan di Laboratorium Genetik dan Pemuliaan, Fakultas Biologi, Universitas Gadjah Mada, Yogyakarta. Dari 241 sukarelawan yang diskrining, 44 sukarelawan didiagnosis sebagai pembawa a-thalasemia, 30 pembawa 107 Nailil Husna et al., Prevalence and distribution of thalassemia trait screening b-thalasemia dan HbE serta satu pembawa a-b-thalasemia. Jumlah pembawa thalasemia tidak menunjukkan perbedaan yang signifikan setiap tahunnya. Prevalensi pembawa thalasemia tinggi, meskipun distribusinya dibatasi oleh lokasi dimana skrining dilakukan.

Background: alpha-Thalassemia is caused primarily by deletions of one to two alpha-globin genes and is characterized by absent or deficient production of alpha-globin protein. The South-East Asia (SEA) deletion, 3.7-kb and 4.2-kb deletions are the most common causes. The present study aimed to observe the molecular characteristics of this common alpha-Thalassemia deletions and analyse its haematological parameter. Methods: Blood samples from 173 healthy volunteers from thalassemia carrier screening in Yogyakarta Special Region were used. Haematological parameters were analysed and used to predict the carrier subjects. Genotype of suspected carriers was determined using multiplex gap-polymerase chain reaction and its haematological parameters were compared. The boundary site of each deletion was determined by analysing the DNA sequences. Results: Seventeen (9.8%) of the volunteers were confirmed to have alpha-Thalassemia trait. Of these, four genotypes were identified namely -α 3.7 /αα (58.8%), -α 4.2 /αα (5.9%), -α 3.7 /-α 4.2 (5.9%) and --SEA /αα (29.4%). The 5′ and 3′ breakpoints of SEA deletion were located at nt165396 and nt184700 of chromosome 16, respectively. The breakpoint regions of 3.7-kb deletion were 176-bp long, whereas for 4.2-kb deletion were 321-bp long. The haematological comparison between normal and those with alpha-Thalassemia trait genotype indicated a significant difference in mean corpuscular volume (MCV) (p< 0.001) and mean corpuscular haemoglobin (MCH) (p< 0.001). As for identifying the number of defective genes, MCH parameter was more reliable (p= 0.003). Conclusions:The resultant molecular and haematological features provide insight and direction for future thalassemia screening program in the region.

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BACKGROUND: β-thalassemia is an inherited blood disorder that relatively common in Southeast Asian countries. In Indonesia, it is estimated that 200,000 infants with thalassemia carrier born each year. Mutation causing β-thalassemia is highly varied and relatively specific in a population. This study aimed to identify the mutations responsible for β-thalassemia from Thalassemia Carrier Screening conducted in Yogyakarta Special Region. This information is beneficial for developing a strategic prevention program to control thalassemia in the region.METHODS: Twenty-eight blood samples of haematologically suspected β-thalassemia from participant of thalassemia screening program in Yogyakarta Special Region were investigated for β-globin gene mutation by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), amplification refractory mutation system (ARMS) and DNA sequencing.RESULTS: Our samples showed average HbA2 value of 5±0.81% and HbF value of 2±2.29%. It showed eight abnormal erythrocyte morphologies dominated by hypochromia (96.4%), cigar cell (85.7%), and microcytosis (78.6%). Our molecular investigation identified three splice-site mutations namely InterVening Sequence (IVS)-1-5 (G>C) (71.4%), IVS-1-2 (T>C) (7.1%), and IVS-1-1 (G>T) (3.6%), two frameshift mutations that are CD35 (-C) (10.7%) and CD8/9 (+G) (3.6%), and a missense mutation of CD6 (GAG>GTG) (3.6%).CONCLUSION: Our study concluded on a high prevalence of IVS-1-5 (G>C) mutation in Yogyakarta Special Region. This mutation information is significant for developing a strategic prevention program to control thalassemia in the region, for example for developing a rapid molecular test for future screening program.KEYWORDS: β-Globin gene, thalassemia, screening, carrier, mutation, Yogyakarta