Richmond Christopher M, Campbell Sally, Foo Hee W, Lunke Sebastian, Stark Zornitza, Moody Amanda, Bannister Elizabeth, Greenway Anthea, Brown Natasha
Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Melbourne, Australia.
School of Medicine, Griffith University, Gold Coast, Australia.
Mol Syndromol. 2020 Feb;11(1):50-55. doi: 10.1159/000505886. Epub 2020 Feb 1.
Heterozygous pathogenic variants in cause autosomal dominant hereditary spherocytosis, an important cause of neonatal nonimmune hemolytic anemia. Biallelic mutations are rarely reported, all with severe neonatal presentation. We describe rapid (68 h) genomic diagnosis of homozygous β-spectrin deficiency in a newborn with severe transfusion-dependent hemolytic anemia, conjugated hyperbilirubinemia, and progressive liver failure. Trio whole-exome sequencing identified a novel biallelic variant (c.6119C>T; p.Thr2040Ile) located in the critical spectrin repeat region. Pretransfusion blood film showed marked spherocytosis including microspherocytes and nucleated erythrocytes, and eosin-5-maleimide (E5M) staining was markedly reduced, supporting pathogenicity. Both asymptomatic heterozygous parents demonstrated mildly reduced E5M staining, with occasional spherocytes and elliptocytes. Early molecular diagnosis facilitated hypertransfusion to suppress ineffective erythropoiesis and reverse hepatic dysfunction. This report broadens the genotypic and phenotypic spectrum of spectrin deficiency and highlights the utility of rapid genomic testing in facilitating early diagnosis and informing targeted therapy in critically ill patients.
杂合致病变体可导致常染色体显性遗传性球形红细胞增多症,这是新生儿非免疫性溶血性贫血的一个重要病因。双等位基因突变鲜有报道,且均表现为严重的新生儿症状。我们描述了对一名患有严重输血依赖性溶血性贫血、结合胆红素血症和进行性肝衰竭的新生儿进行纯合β-血影蛋白缺乏症的快速(68小时)基因组诊断。三联体全外显子测序鉴定出一个位于关键血影蛋白重复区域的新型双等位基因变体(c.6119C>T;p.Thr2040Ile)。输血前血涂片显示明显的球形红细胞增多,包括小红细胞和有核红细胞,且嗜酸性-5-马来酰亚胺(E5M)染色明显减少,支持其致病性。两名无症状的杂合子父母的E5M染色均轻度减少,偶见球形红细胞和椭圆形红细胞。早期分子诊断有助于强化输血以抑制无效红细胞生成并逆转肝功能障碍。本报告拓宽了血影蛋白缺乏症的基因型和表型谱,并强调了快速基因组检测在促进危重症患者早期诊断和指导靶向治疗方面的作用。