Molecular basis and hematological features of hemoglobin variants in Southern Thailand

Abstract

Hemoglobinopathy (abnormal hemoglobin or hemoglobin variant) is an inherited disorder that results in the abnormal structure of globin chains of the hemoglobin (Hb) molecule. Many abnormal Hbs have been characterized worldwide, including more than 20 variants in Thailand. The Bio-Rad Variant II HPLC system is used for investigating hemoglobin variants at Songklanagarind Hospital. This system has been shown to be a sensitive, specific, and reproducible method, but some hemoglobin variants such as Hb Tak and Hb D-Punjab cannot, as yet, be clearly separated by this method. The aim of this study was to investigate the prevalence of hemoglobinopathy in southern Thailand using DNA sequencing and study the severity of each hemoglobin variant. A total of 58 hemoglobin variant samples were obtained from blood samples undergoing routine hemoglobin typing at Songklanagarind Hospital. Genomic DNAs were extracted from the samples, and the globin genes were analyzed by using PCR-direct sequencing. The molecular analysis revealed eight hemoglobin variants: 28 Hb C, 12 Hb D-Punjab, 7 Hb Tak, 4 Hb G-Makassar, 2 Hb Lepore-Hollandia, 2 Hb Q-Thailand, 2 Hb O-Indonesia, and 1 Hb Hope. The distribution of hemoglobin variants in southern Thailand is associated with geographic and/or ethnic backgrounds. This study may help hematologists understand better the prevalence of hemoglobin variants and their hematological features in this region.

Clinical and haematological characteristics of 38 individuals with Hb G‐Makassar in Malaysia

“…Our cohort of cases is larger than the reported cases in Thailand [2–4]. The variant was exclusively found among the Malays, with the majority of them from Terengganu ( n = 20/38, 52.6%).…”

“…Hb G‐Makassar is considered a benign Hb variant. The patients may present with no symptom or mild anaemia, be it for those with Hb G‐Makassar heterozygote (NG_000007.3:g.[70614A > C];[70614A =]) or homozygote (NG_000007.3:g.[70614A > C];[70614A > C]); or those with a compound Hb G‐Makassar/β‐globin variant [1–6]. In contrast, Hb S has a spectrum of clinical presentation according to the interaction of the variant with different genotypes in HBB allele.…”

First case of Hb Fontainebleau with sickle haemoglobin and other non-deletional α gene variants identified in neonates during newborn screening for sickle cell disorders

“…It has been reported earlier in the Buginese from Sulawesi, Makassars, Iranian, South African, Italian and Chinese populations 18 19. So far, there have been only two cases reported from India 11 20.…”

Scanning for α‐Hemoglobin Variants by High‐Resolution Melting Analysis

“…Only few cases of these rare α-Hb variants found in several races had been reported. Hb Kurosaki, Hb O-Indonesia, and particular Hb J-Buda were very rare Hb variants occurred in Thai, Japanese, Sulawesi, and Indian populations (15)(16)(17)(18)(19)(20)(21)(22). Hb G-Waimanalo had been reported with 12.19% frequency in Eastern Guangdong, China, but it is a first report here in Thai population (23).…”