Case#: 15-year-old Chinese boy

DiseaseAssertion: Patient was diagnosed with systemic lupus erythematosus (SLE) at a young age and was recently found to carry heterozygous mutations in PIK3CD. Diagnoses: Activated PI3Kδ syndrome

FamilyInfo: Family history revealed that his mother died of gastric cancer. Whole exome sequencing was performed in patient and in his father, when he was at the age of 15 and the PIK3CD gene was found to exhibit good coverage.

CasePresentingHPOs: HP:0002725, HP:0005425, HP:0032218, HP:0002716, HP:0000093, HP:0020072, HP:0000790, HP:0001882, HP:0001903, HP:0003493, HP:0025289, HP:0001744, HP:0004322, HP:0550004, HP:0001873, HP:0003565, HP:0011227, HP:0020026, HP:0032230, HP:0002110, HP:6001383, HP:0033726, HP:0033493, HP:0012574

CaseHPOFreeText: Serum level of complements was low, such as C3, C4, and CH50. Serum level of IgM and IgE was elevated, but IgG and IgA was normal. Lung CT scan showed partial consolidation of left upper lung with bronchiectasis and left upper bronchial stenosis. Renal biopsy was also done because of persistent hematuria and proteinuria, and it displayed moderately increased mesangial matrix and mesangial hypercellularity under the light microscope; subepithelial deposits was noted, and some mesangial changes may be present as seen in electron microscopy. Immunofluorescence was positive for C1q, C3, IgG, IgM, and Fb (Fig. 2). The patient was given oral prednisolone and hydroxychloroquine combined with mycophenolate mofetil. Six months later, the level of complement was restored to normal, hematuria and proteinuria disappeared, and liver function returned to normal. He was currently receiving intravenous immunoglobulin in association with hydroxychloroquine, low-dose prednisolone, and mycophenolate mofetil, with a good efficacy.

CasePreviousTesting: NR

GenotypingMethod: Whole exome sequencing, Sanger sequencing

PreviouslyPublished: No

Variant: NM_005026.5:c.3061G>A

ClinVar: 88675

gnomAD: chr1-9726972-G-A

SupplementalData: Figure 1, 2, 3