Hassan Suha Mustafa, Alrawas Abdulhakim, Al Khanbashi Laila, Wali Yasser
Department of Hematology, Sultan Qaboos University, Muscat, Oman.
Department of Child Health, Sultan Qaboos University, Muscat, Oman.
BMJ Case Rep. 2023 Apr 4;16(4):e254416. doi: 10.1136/bcr-2022-254416.
Beta-thalassaemia is one of the most common genetic disorders worldwide, which is caused by absent or decreased synthesis of beta-globin chain subunits. Beta-thalassaemias are diverse groups of disease with a wide spectrum of clinical phenotypes. The clinical phenotypes can include asymptomatic forms of beta-thalassaemia minor, intermediate and severe transfusion dependent beta-thalassaemia major. Clinical severity varies depending on the underlying β globin gene mutation. There are a number of mild β-thalassaemia gene defects that could be referred as a 'silent carrier'. Identifying the underlying molecular defect is essential to predict phenotype severity for optimal management, tailored treatment and improved quality of life.We report the first identification of a homozygous point mutation located within the promoter region of the β-globin gene at position -71 (C>T). The patient was a female child, who was referred to our clinic after she was found to have hypochromic microcytic anaemia with low haemoglobin (Hb) (67 g/L) and an Hb A level at the upper limit of the normal value (3.7%). This observation is a new example of homozygous mild β-thalassaemia with a borderline Hb A level, and illustrates a potential source of pitfall in the diagnosis of β-thalassaemia disease.
β地中海贫血是全球最常见的遗传性疾病之一，由β珠蛋白链亚基合成缺失或减少所致。β地中海贫血是一组具有广泛临床表型的多种疾病。临床表型可包括无症状的轻型β地中海贫血、中间型以及重度依赖输血的重型β地中海贫血。临床严重程度取决于潜在的β珠蛋白基因突变。有许多轻度β地中海贫血基因缺陷可被称为“静止型携带者”。确定潜在的分子缺陷对于预测表型严重程度以进行最佳管理、量身定制治疗方案和提高生活质量至关重要。我们报告首次鉴定出位于β珠蛋白基因启动子区域-71位（C>T）的纯合点突变。该患者为一名女童，在被发现患有低色素小细胞贫血、血红蛋白（Hb）水平低（67 g/L）且Hb A水平处于正常值上限（3.7%）后转诊至我们的诊所。这一观察结果是具有临界Hb A水平的纯合轻型β地中海贫血的一个新例子，并说明了β地中海贫血疾病诊断中潜在的陷阱来源。
