Clinical And Molecular Analysis Of IPEX And XLP-1

Part one: A novel FOXP3gene mutation with variant transcript ina Chinese patient with immune dysregulation, polyendocrinopathy,enteropathy, X-linked syndromeObjective: To investigate the clinical characteristics, genetic variationof FOXP3gene, frequency of regulatory T cells (Treg) and expression ofFOXP3protein in the peripheral mononuclear cells (PBMCs) in a2month-old male patient with severe and early-onset diarrhea, subclinicalhypothyroidism, thyroiditis, immune thrombocytopenic purpura andautoimmune hemolytic anemia.Methods: The patient was highly suspected with IPEX syndrome andwas subjected to detection of FOXP3protein expression on CD4+CD25+Tcells and the frequency of Treg in CD4+T cells by flow cytometry. FOXP3gene and its transcripts were amplificated by PCR. The PCR products werecloned and sequenced. One hundred healthy controls were also enrolled inthis study to exclude SNP.Results: The patient showed significantly reduced frequency of Tregbut normal expression of FOXP3protein in his peripheral blood whencompared with healthy controls. A G>A substitution located in the lastnucleotide of exon8resulting in E323K substitution was identified, which also resulted in several disease-causing transcript variations. The patient’smother was identified as a carrier of the same mutation.No mutation wasfound at the same site of FOXP3gene in the healthy controls.Conclusion: A novel splice recognizing site mutation of FOXP3wasidentified in a Chinese IPEX syndrom patient with decreased frequency ofTreg. Patient with severe and early-onset diarrhea, subclinicalhypothyroidism, thyroiditis, immune thrombocytopenic purpura andautoimmune hemolytic anemia should be suspected as IPEX and FOXP3gene analysis should be performed for final diagnosis. Part two:Clinical, genetic and proteinic characteristics of X-linkedlymphoproliferative syndrome type1Objective: To investigate the clinical, immunological,genetic andproteinic characteristics of patients with XLP-1caused by mutation ofSH2D1A for providing useful messages on clinical diagnosis.Methods: Firstly, the clinical data and laboratory inspection results of15XLP-1-like patients was analyzed. Then, the flow cytometry was used todetect the SAP expression in PBMCs of patients and their mothers. DNAand RNA was extracted from peripheral blood of patients and their maternalrelatives followed by PCR to amplify SH2D1A gene and its transcripts. Atlast, the PCR products were cloned and sequenced.Results: Three different mutations of SH2D1A were found in patients from3nonconsanguineous families through gene analysis, and2of them arenovel mutations.Mother, grandmother of patient1and mother of patient2were identified as carriers of the same mutation, respectively. Both P1andP2showed a decreased expression of SAP. Mother of P1showed a biomodalpattern of SAP while mother of P2showed almost normal expression.Conclusion: Three XLP-1patients caused by different mutations ofSH2D1A were identified. Patients with clinical manifestation of XLP-1should approach for gene analysis and detection of SAP expression.