case_images: PMC11338812_01
case_images: Photograph of a 4-month-old patient with SCID complicated by systemic disseminated BCG disease caused by a novel IL2RG gene mutation. (A) Scattered subcutaneous nodules on the trunk, with ulceration and scabbing visible below the ear and in the upper left abdomen. (B) Scattered rashes and purplish-blue subcutaneous nodules on the lower limbs, with some scabs forming. (C) Unhealed BCG vaccination site with liquid leakage.
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case_images: These did not fade under pressure, and some were ulcerated and scabbed ( Figures 1A, B ). The BCG vaccination site exhibited rupture with fluid exudation ( Figure 1C ).
case_images: Chest computed tomography (CT) and cytological examination. (A) Chest CT lung window. (B) Chest CT mediastinal window showing scattered inflammation in both lungs. (C) Bone marrow specimen demonstrating significant proliferation and activation of bone marrow, with toxic particles and vacuolar degeneration visible in granulocytes. Red blood cells are mainly composed of middle- and late-stage erythrocytes, and no plate-producing megakaryocytes are present. (D) Rash imprint showing approximately 18% of suspected Langerhans tissue cells, with abundant cytoplasm filled with small grayish-purple particles. The nucleoli are circular or irregular in shape, and the cytoplasm is thick and loose.
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case_images: Chest computed tomography (CT) revealed slight inflammation in both lungs ( Figures 2A, B ). Bone marrow examination revealed active hyperplasia of bone marrow, neutrophils with toxic granulation and vacuoles, iron-deficient erythroid cells, and poor platelet production in megakaryocytes ( Figure 2C ). Langerhans cells were found on the skin print ( Figure 2D ) and the bovine M. tuberculosis complex was detected in the blood using metagenomic next-generation sequencing (mNGS) technology.
case_images: IL2RG gene mutation detected in the present case. (A) Sanger chromatogram. (B) Schematic diagram of the mutation sites. (C) Schematic diagram of the mutation protein.
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case_images: Whole-exome and Sanger sequencing revealed a microdeletion insertion mutation in exon 3 of the IL2RG gene (chrX: 70330490-70330492), resulting in a frameshift mutation at the amino acid level of the coding protein IL2RG (NM_000206.3) gene, c.316_318 delins GTGAT p.Leu106ValfsTer42 ( Figures 3A, B ). This mutation was expected to cause the 106th amino acid in the protein amino acid sequence to change to valine from leucine and result in an early stop codon at the 147th amino acid, terminating translation at the 42nd amino acid and producing a truncated protein that differs from the original sequence ( Figure 3C ).