Case Presentation
Case#: 2 year old female
DiseaseAssertion: APDS (She was diagnosed with polymorphous B-cell lymphoproliferative disorder)
FamilyInfo: no family history suggestive of an immunodeficiency
CaseHPOFreeText: referred by pulmonary to clinical immunology for evaluation of her recurrent pneumonias and bronchiectasis. Work-up at that time revealed IgA < 6 (34–305 mg/dL), IgG 30 (572–1,474 mg/dL), IgM 1190 (31–208 mg/dL). In addition to low levels of IgG and IgA but elevated IgM levels, immune evaluation revealed T and B cell lymphopenia −827 (876–3,394 CU MM) and 28 (200–1,259/CU MM), respectively. Her CD4 count was 331 (412–2,095/CU MM) and CD8 count was 481 (236–995/CU MM). She had a normal response to lymphocyte mitogen and antigen stimulation. Due to these results and her clinical history, she was started on intravenous immunoglobulin replacement which helped decrease her incidence of infections. As she grew older she began to have increased hospitalizations for hemolytic anemia and recurrent pneumonias and sinusitis. She also developed lymphadenopathy and splenomegaly. She received rituximab with resultant improvement in her counts and decrease in size of her lymphadenopathy and hepatosplenomegaly. She was also started on trimethoprim/sufamethoxazole prophylaxis to help prevent infections, and though she continued to have intermittent respiratory infections the amount was improved. In addition to asymmetrical cervical lymphadenopathy and parotid gland enlargement Figures 2A,B, a CT neck/chest/abdomen and pelvis done at that time showed mediastinal, hilar, abdominal, and pelvic lymphadenopathy, impressive retroperitoneal lymphadenopathy, hepatosplenomegaly, and cecum and terminal ileum thickening Figures 2C,D.
CasePreviousTesting: Genetic testing revealed no mutation in AID, UNG, CD40, or CD40L but later gene sequencing discovered a dominant activating mutation in PIK3CD–c.3061G > A (p.Glu1021Lys).
GenotypingMethod:
Variant: PIK3CD–c.3061G > A (p.Glu1021Lys).
CAID: CA145460
gnomAD: absent in gnomAD v2.1.1