BACKGROUND Crigler Najjar type 1 is a rare autosomal recessive condition caused by the absence of UDPGT enzyme due to mutations in the UGT1A1 gene. This enzyme is responsible for elimination of unconjugated bilirubin from the body by glucuronidation. Affected individuals are at risk for kernicterus and require lifelong phototherapy. Liver transplant is the only definitive treatment. CASE PRESENTATION Here we report a case of a 6 month old Sudanese female infant with CN1 whose molecular analysis revealed a novel homozygous 22 base pair duplication (c.55_76dup) in the coding exon 1 of the UGT1A1 gene. This 22 bp duplication causes a frame shift leading to a premature stop codon. She underwent a successful liver transplant at 7 months of age and is doing well at 1 year follow-up. CONCLUSION This study shows that molecular diagnosis helps in precise diagnosis of CN1 and in prognosis, prompt medical intervention and appropriate therapy. This particular 22 bp duplication within the coding region of UGT1A1 can be a founder mutation in the Sudanese population.

中文翻译：

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在一例I型Crigler-Najjar综合征的苏丹婴儿中，UGT1A1外显子1内新的22 bp复制的病例报告。

背景Crigler Najjar 1型是一种罕见的常染色体隐性遗传病，由UGT1A1基因突变引起的UDPGT酶缺失引起。该酶负责通过葡萄糖醛酸化作用从体内消除未结合的胆红素。受影响的个体有发生角膜炎的风险，需要终生光疗。肝移植是唯一的确定性治疗。病例介绍在这里我们报道了一个6个月大的苏丹CN1女婴，其分子分析揭示了在UGT1A1基因的编码外显子1中有一个新的纯合的22个碱基对重复（c.55_76dup）。该22bp的重复引起移码，导致过早的终止密码子。她在7个月大时进行了成功的肝移植，并且在1年的随访中表现良好。结论这项研究表明分子诊断有助于CN1的准确诊断和预后，及时的医疗干预和适当的治疗。UGT1A1编码区内的特定22 bp复制可能是苏丹人口中的奠基人突变。