Two cases of adenosine deaminase 2 deficiency in children and literature review / 中华实用儿科临床杂志

ABSTRACT

Objective:To summarize the clinical phenotype and genotype features of 2 children with adenosine deaminase 2 (ADA2) deficiency, and to review the related literature so as to enhance the understanding of this disease.Methods:The phenotype and genotype of 2 cases with ADA2 deficiency who visited the Affiliated Hospital of Qingdao University from March to December 2019 were analyzed.Literature was searched from foreign and domestic databases and studied to summarize clinical and gene mutation characteristics of children with ADA2 deficiency.Results:(1) ADA2 gene mutation was found in both children.One case was characterized by recurrent fever, livedo reticularis, polyarteritis nodosa and immunodeficiency.The mutation site c. 571delC(p.Q191Sfs*5)of the ADA2 gene detected in this case was a homozygous mutation, which was a new mutation point and not reported in China or abroad previously.The other case was characterized by recurrent fever, panniculitis, vasculitis with legs, and immunodeficiency.The mutation site c. 1358A>G(p.Y453C)was a homozygous mutation that was not reported in China previously.(2)There were 171 cases of children diagnosed with ADA2 deficiency in foreign countries, but only 5 cases (3 previously reported cases and 2 cases in this study) were detected in China.The main clinical phenotypes were recurrent fever(5/5 cases), livedo reticularis(4/5 cases), panniculitis(1/5 cases), cutaneous gangrene(1/5 cases), growth retardation(1/5 cases), cerebral infarction(3/5 cases), humoral immunodeficiency(4/5 cases), blood system involvement(3/5 cases), and myalgia(2/5 cases), elevated inflammatory markers(C-reactive protein, erythrocyte sedimentation rate)(5/5 cases). Conclusions:Children with ADA2 deficiency have various clinical phenotypes, and a good understanding of phenotypes can improve the level of clinical diagnosis and treatment.The mutation point of c. 571delC is a novel ADA2 gene mutation type, which further enriches the ADA2 gene spectrum.