Congenital atransferrinemia is an extremely rare autosomal recessive disorder resulting in the complete absence or extremely reduced amount of transferrin. In this study, we describe the first case of congenital atransferrinemia in Tunisia and the 18th patient in the reported data. The patient was referred to our hospital to explore a severe hypochromic and microcytic anemia. The laboratory evaluation including hematological and biochemical examination was performed in the proband and her parents. All exons of the transferrin gene were PCR amplified. The products were screened for mutations by direct sequencing.

Based on laboratory and clinical findings, diagnosis of congenital atransferrinemia was confirmed. DNA sequencing revealed the presence of a novel homozygous deletion (c.293-63del) in the intron 13. This mutation is predicted to generate a higher score cryptic branch point leading to the production of an altered mRNA molecule. The second previously reported missense mutation p.Arg609Trp. Crystallographic structure analyzes demonstrate that the mutation would probably lead to significant conformational change not allowing the expression of transferrin protein.

Current molecular characterization of this novel transferrin abnormality puts to the proof the variability in onset, first blood transfusion, and phenotypic expression in atransferrinemic patients.

先天性转铁蛋白血症是一种极为罕见的常染色体隐性遗传疾病，可导致完全不存在或极少的转铁蛋白。在这项研究中，我们描述了突尼斯的第一例先天性转铁蛋白血症，在报告的数据中描述了第18例患者。该患者被转诊至我院，以探讨严重的低色性和小细胞性贫血。在先证者及其父母中进行了包括血液学和生化检查在内的实验室评估。对运铁蛋白基因的所有外显子进行PCR扩增。通过直接测序筛选产物的突变。

根据实验室和临床发现，确定了先天性转铁蛋白血症的诊断。DNA测序揭示内含子13中存在新的纯合缺失（c.293-63del）。预计该突变会产生较高分数的隐性分支点，导致产生改变的mRNA分子。先前报道的第二个错义突变p.Arg609Trp。晶体结构分析表明，该突变可能导致显着的构象变化，不允许运铁蛋白的表达。

目前这种新型转铁蛋白异常的分子特征证明了转铁蛋白血症患者发病，首次输血和表型表达的变异性。