Clinical and Molecular Characteristics of Non-Transfusion-Dependent Thalassemia in Kuwait

Although not regularly transfused, patients with non-transfusion-dependent thalassemia (NTDT) are prone to iron overload and its complications. Their molecular, phenotypical and laboratory characteristics vary in different populations and there is a need to document local prevailing patterns. We have reviewed the records of our patients with NTDT in Kuwait and documented their clinical and molecular characteristics in addition to iron status [serum ferritin and liver magnetic resonance imaging (MRI) T2*], management and complications. There were 41 patients, made up of 20 with beta-thalassemia intermedia (beta-TI), 18 with Hb H (beta 4) disease and three with Hb E (HBB: c.79G > A)-beta-thalassemia (Hb E-beta-thal); their ages ranged from 3 to 36 years (mean 12.5 +/- 7.7). While 18 (43.9%) had been transfused at least once, only three (7.3%) had been transfused on multiple occasions. Three patients had serum ferritin >500 ng/mL; while four of 38 had mild or moderate liver iron overload. Seven (35.0%) of the beta-TI patients were managed with hydroxyurea (HU) with good response. Other complications included five patients with gallstones and one each of hypothyroidism and moyamoya. The most common mutations among the beta-TI patients were IVS-II-1 (G>A) and IVS-I-6 (T>C), while among the Hb H patients, the Saudi alpha 2-globin gene polyadenylation (polyA) (AATAAA>AATAAG) mutation was responsible for all cases either as homozygotes (61.1%) or compound heterozygotes with the alpha-thal-2 (-alpha(3.7)) allele (33.3%). Although the pattern of NTDT in Kuwaiti patients is generally mild, there is a need to follow them to adulthood as the complications are cumulative and more prevalent in this group.